Coding apparatus for digital image signals

A coding apparatus for a digital image signal includes a circuit (5) to which a digital image signal which has been converted into a signal having a two-dimensional block structure is supplied, and which is such that between first and second blocks which are located at spatially the same position and respectively belong to two sequential frames, the first block is always transmitted and transmission/non-transmission of the second block is adaptively executed. A control circuit (5) controls the transmission/non-transmission of the second block in accordance with an absolute value of a difference between values of pixel data at the same position in the first and second blocks, and a coding circuit (18) to which the pixel data of a second block which is to be transmitted are supplied compression encodes the pixel data on a block unit basis.