The present disclosure provides a video encoding/decoding apparatus and method. According to one embodiment, the video encoding and decoding apparatus includes: an image encoder for reducing horizontal and vertical sizes of a variable macro block into a set size or by a set ratio with the variable macro block reset in a smaller size than the current size, if the variable macro block for the current encoding is not inside an input image, and predictive encoding based on the reset variable macro block; and an image decoder for decoding by reducing the size of the variable macro block for the current decoding into the set size or by set ratio with the variable macro block reset in a smaller size than the current size, if the variable macro block of the current decoding target is not inside an input image.