A selecting unit selects, from plural intra prediction modes, the intra prediction mode to be used for intra prediction coding of a target coding block. A coding unit performs the intra prediction coding to a frame constituted by plural blocks in units of the block, in the intra prediction mode selected by the selecting unit. Further, in a case where inter prediction coding can be used as a coding system of the frame in which the target coding block is included, the selecting unit considers the neighboring blocks of the target coding block to have been coded with the inter prediction and selects the intra prediction mode to be used for the intra prediction coding of the target coding block from among the plural intra prediction modes.