An image compression apparatus capable of efficiently encoding an image without causing color deviation to the eye compresses luminance element image data and two types of chrominance element image data each consisting of a plurality of blocks. The image compression apparatus includes: a resolution determination processing section (38, 142) adaptively setting a resolution of each block during reduction according to a predetermined criterion for each of the luminance element image data and the two types of chrominance element image data, and creating resolution information; a data creation processing section (44) connected to the resolution determination processing section (38, 142), and creating data having each block reduced based on the resolution information for each of the luminance element image data and the two types of chrominance element image data; and an encoder (42, 48A, 48B) connected to the resolution determination section (38, 142) and the data creation processing section (44), and encoding an output of each of the resolution information and the data creation processing section (44).