In generation of a wedgelet pattern, all the patterns are generated through a line segment drawing process and a region filling process. Therefore, there is a problem that a processing amount is large.A moving image decoding device (1) includes: a wedgelet pattern generation section (145T4) that generates a wedge pattern; a rotation pattern generation section (1465) that derives a rotation pattern by rotating the wedge pattern; a pattern storage section (1464) that adds the rotation pattern to a wedge pattern table; and a DC prediction value derivation section (145T3) that derives a prediction value of each region partitioned in the wedge pattern included in the wedge pattern table (145T5).