The image coding apparatus is provided to realize image coding with little calculation quantity and through rate distortion optimization thereby maintaining a favorable image quality. The image coding apparatus includes a processing unit that conducts frequency transform and quantization on a block in a predetermined manner for a plurality of coding modes, each mode having a different coding process, a cost calculating unit that calculates a predictive coded quantity and coding distortion in a coding mode using a result of the quantization conducted by the processing unit and a residue to obtain a cost regarding the coding mode, a minimum coding cost selecting unit that selects a minimum coding cost among the coding costs calculated for respective coding modes, and a coding unit that conducts coding on the blocks in a coding mode associated with the minimum coding cost selected by the minimum coding cost selecting unit.