We Claim:
1. An image encoding device comprising:
an encoding controlling unit (1) for selecting a coding mode to be applied to individual coding blocks that are obtained by hierarchically dividing a coding block having a maximum size for a coding process;
a prediction image generating unit (3, 4, 5) for generating an intra prediction image or an inter prediction image by performing, based on the selected coding mode, an intra prediction or an inter prediction on the individual coding blocks;
a loop filter unit (11) for performing a loop filter process on a local decoded image obtained by adding a local decoded prediction signal and the intra prediction image or the inter prediction image, the local decoded prediction signal being obtained by performing an inverse transformation process on compressed data of a difference image; and
a variable length encoding unit (13) for generating coded data by performing a variable length coding on the coding mode of the coding block, an intra prediction parameter used for generating a prediction image by performing an intra prediction on a partition in the coding block, and compressed data generated from a difference between an original image and the intra prediction image or the inter prediction image,
wherein,
the variable length encoding unit (13) performs a variable length coding on an intra merge flag indicating whether or not said intra prediction parameter for said partition is identical to an intra prediction parameter for an adjacent partition located to top or left of said partition,
when there are two or more adjacent partitions located above or to the left of said partition, a first partition in a direction away from top left of said partition is regarded as said adjacent partition,
when said intra prediction parameter for said partition is identical to an intra parameter for said adjacent partition located to top or left of said partition, said variable length encoding unit (13) generates an intra merge direction specifying one of adjacent

partitions located above and to the left of said partition of which intra prediction parameter is identical to said intra prediction parameter, and
when said intra prediction parameter for said partition is not identical to an intra prediction parameter for an adjacent partition located above or to the left of said partition, said variable length coding unit (13) performs a coding on said intra prediction parameter for said partition.
2. An image decoding device comprising:
a variable length decoding unit (21) for performing a variable length decoding on coded data of coding blocks hierarchically divided until reaching an upper limit of a number of hierarchical layers to obtain a coding mode and compressed data of each of the coding blocks;
a prediction image generating unit (22, 23, 24) for generating an intra prediction image or an inter prediction image by performing, based on the obtained coding mode, an intra prediction or an inter prediction on the individual coding blocks;
a loop filter unit (28) for performing a loop filter process on a decoded image obtained by adding a decoded prediction difference signal and the intra prediction image or the inter prediction image, the decoded prediction difference signal being obtained by performing an inverse transformation process on the compressed data; and
a decoded image generating unit (26) for generating a decoded image by adding the intra prediction image or the inter prediction image generated by the prediction image generating unit (22, 23, 24) and a difference image obtained by decoding the compressed data,
wherein,
when there are two or more adjacent partitions located above or to the left of said partition, a first partition in a direction away from top left of said partition is regarded as said adjacent partition,
the variable length decoding unit (21) decodes an intra merge flag indicating whether or not said intra prediction parameter for said partition is identical to an intra

prediction parameter for an adjacent partition located to top or left of said partition,
when said intra prediction parameter for said partition is identical to an intra parameter for said adjacent partition located to top or left of said partition, said variable length decoding unit (21) decodes an intra merge direction specifying one of adjacent partitions located above and to the left of said partition of which intra prediction parameter is identical to said intra prediction parameter, and
when said intra prediction parameter for said partition is not identical to an intra prediction parameter for an adjacent partition located above or to the left of said partition, said variable length decoding unit (21) decodes an intra prediction parameter for said partition.