PURPOSE: To reduce a bit rate while maintaining the high quality characteristic of a source picture signal and to realize high-efficiency transmission concerning the sub band encoding system used for the digital transmission of high-fidelity picture signals.

CONSTITUTION: A differential signal generating means 13 is provided to select the differential signal of lowest power among differential signals between adjacent picture elements between movement compensating frames or fields or in the field concerning the input picture signal, and a complete reproduction type band dividing means 42 is provided to reduce the differential signal horizontally or vertically at least and to divide the signal into respective band signals in a high frequency. Then, an encoding means 45 is provided to execute the entropy encoding of each band signal.