WE CLAIM:
1. A quality analysis device, comprising:
a data aggregation unit for acquiring quality data indicating a state of an object subjected to quality analysis and apparatus-information data indicating information of an apparatus that handles the object subjected to quality analysis;
a condition setting unit for setting, with respect to the quality data and the apparatus-information data acquired by the data aggregation unit, data items of data to be counted up, a base condition indicating a condition that constitutes a basis of the quality analysis, and a comparison condition indicating a condition subjected to the quality analysis; and
a distribution difference calculation unit for extracting from the quality data and the apparatus - information data acquired by the data aggregation unit, data that meets the base condition and data that meets the comparison condition, for each data item set by the condition setting unit, and calculating frequency distributions of these data for each of the data items, and outputting data indicating a degree of divergence between the frequency distribution of the base condition and the frequency distribution of the comparison condition.

2. The quality analysis device of Claim 1, further
comprising a data-type classification unit for
classifying the quality data and the
apparatus - information data acquired by the data aggregation unit, into respective set types;
wherein the distribution difference calculation unit uses data classified by the data-type classification unit, instead of the quality data and the apparatus - information data acquired by the data aggregation unit.
3. The quality analysis device of Claim 1 or 2,
wherein the condition setting unit sets the data
items, the base condition and the comparison condition, in accordance with data items, a base condition and a comparison condition which are indicated from outside.
4. The quality analysis device of Claim 1 or 2,
wherein the data aggregation unit acquires event data
indicating what event has occurred in relation to the apparatus,
the quality analysis device further comprising an event-effect analysis unit for specifying the data item in which the degree of divergence by the distribution

difference calculation unit is equal to or more than a set value, as a factor candidate that is likely to cause trouble, and outputting data indicating a relationship between values of the factor candidate in a specified period of time and the event data.
5. A quality analysis method, comprising:
acquiring, by a data aggregation unit, quality data indicating a state of an object subjected to quality analysis and apparatus-information data indicating information of an apparatus that handles the object subjected to quality analysis;
setting, by a condition setting unit, data items of data to be counted up, a base condition indicating a condition that constitutes a basis of the quality analysis, and a comparison condition indicating a condition subjected to the quality analysis, with respect to the quality data and the apparatus-information data acquired in the data aggregation step; and
extracting, by a distribution difference calculation unit, from the quality data and the apparatus - information data acquired in the data aggregation step, data that meets the base condition and data that meets the comparison condition, for each data item set in the condition setting step, and calculating

frequency distributions of these data for each of the data items, and outputting data indicating a degree of divergence between the frequency distribution of the base condition and the frequency distribution of the comparison condition.