WE CLAIM:
1. An operation input device comprising:
a knob for operations, disposed in a display region of a touch display;
a conductor column that is provided in the knob, and that can be detected as a touch point irrespective of whether or not the knob is in a state of being touched with user’s finger;
a touch point detecting unit for detecting a plurality of touch points including the touch point corresponding to the conductor column, and outputting touch information related to the plurality of detected touch points;
a knob touch point determining unit for determining, by using the touch information, the touch point corresponding to the conductor column among the plurality of touch points detected by the touch point detecting unit;
a touch strength value calculating unit for calculating a touch strength value at the touch point corresponding to the conductor column by using the touch information and a determination result by the knob touch point determining unit; and
a finger-touch-on-the-knob determining unit for determining, by using the touch strength value, whether or not the knob is in a state of being touched with user’s finger.
2. The operation input device according to claim 1, wherein
by executing threshold-value determination processing in which the

touch strength value is used, the finger-touch-on-the-knob determining unit determines whether or not the knob is in a state of being touched with user’s finger.
3. The operation input device according to claim 2, comprising:
a touch coordinate value obtaining unit for obtaining touch
coordinate values of the touch point corresponding to the conductor column by using the touch information and the determination result by the knob touch point determining unit;
a knob operation determining unit for determining, on a basis of changes in the touch coordinate values with respect to time, whether or not the knob is in a state of being operated; and
a threshold value setting unit for setting a threshold value in the threshold-value determination processing by using the touch strength value obtained in the state in which the knob is being operated.
4. The operation input device according to claim 2, wherein
when the determination result indicating that the touch strength
value is lower than the threshold value, or lower than or equal to the threshold value, is obtained a reference number of times in succession in the threshold-value determination processing, the finger-touch-on-the-knob determining unit settles the determination result.
5. An operation input device comprising:
a knob for operations, disposed in a display region of a touch

display;
a conductor column that is provided in the knob, and that can be detected as a touch point irrespective of whether or not the knob is in a state of being touched with user’s finger;
a touch point detecting unit for detecting a plurality of touch points including the touch point corresponding to the conductor column, and outputting touch information related to the plurality of detected touch points;
a knob touch point determining unit for determining, by using the touch information, the touch point corresponding to the conductor column among the plurality of touch points detected by the touch point detecting unit;
a touch coordinate value obtaining unit for obtaining touch coordinate values of the touch point corresponding to the conductor column by using the touch information and a determination result by the knob touch point determining unit; and
a finger-touch-on-the-knob determining unit for determining, on a basis of changes in the touch coordinate values with respect to time, whether or not the knob is in a state of being touched with user’s finger.
6. The operation input device according to claim 5, wherein
the finger-touch-on-the-knob determining unit calculates amounts of changes in the touch coordinate values with respect to the time, obtains estimated values of difference values between the touch coordinate values in the state in which the knob is being touched with user’s finger and the

touch coordinate values in a state in which the knob is being touched with user’s finger, and compares values of the amounts of changes with the estimated values to determine whether or not the knob is being touched with user’s finger.
7. The operation input device according to claim 5, wherein
the finger-touch-on-the-knob determining unit calculates amounts of changes in the touch coordinate values over a reference time and executes threshold-value determining processing in which values of the amounts of changes are used to determine whether or not the knob is being touched with user’s finger.
8. An operation input device comprising:
a knob for operations, disposed in a display region of a touch display;
a conductor column provided in the knob, and each including a first conductor column that can be detected as a touch point irrespective of whether or not the knob is in a state of being touched with user’s finger, and a second conductor column that can be detected as a touch point only in the state in which the knob is being touched with user’s finger;
a touch point detecting unit for detecting a plurality of touch points including the touch point corresponding to the conductor column, and outputting touch information related to the plurality of detected touch points;
a knob touch point determining unit for determining, by using the

touch information, the touch point corresponding to the conductor column among the plurality of touch points detected by the touch point detecting unit; and
a finger-touch-on-the-knob determining unit for determining, on a basis of the number of touch points included in a determination result by the knob touch point determining unit, whether or not the knob is in a state of being touched with user’s finger.
9. The operation input device according to claim 8, wherein
the knob has a structure in which the number of touch points
included in the determination result by the knob touch point determining unit differs depending on a state of being grasped by the user.
10. The operation input device according to any one of claims 1 to 9,
comprising:
a finger touch point determining unit for determining, by using the touch information and the determination result by the knob touch point determining unit, a touch point corresponding to the finger of the user among the plurality of touch points detected by the touch point detecting unit; and
a disabled area setting unit for setting an operation disabled area in which operation input by a touch point corresponding to the finger of the user is disabled,
wherein the disabled area setting unit sets the operation disabled areas that differ from each other between the state in which the knob is

being touched with user’s finger and a state in which the knob is not being touched with user’s finger.
11. The operation input device according to claim 10, comprising a display control unit for causing an image corresponding to the operation disabled area to be displayed in the display region.