To provide an apparatus and method for detecting a motion vector, which can reduce computational complexity of image coding processing while contributing to improvement of image quality and coding efficiency, and which can achieve high-speed processing and low power consumption.

The apparatus for detecting a motion vector comprises an image data memory 101 for storing pixel values of a coding subject picture and a plurality of reference pictures, an initial search start position determination part 102 for selecting positions other than a position indicated by a zero vector on a block as a coding subject as an initial search start position of sequential search, and a motion search part 103 for searching a motion vector by the sequential search. The initial search start position determination part 102 sets the initial search start position of at least one reference picture in relation of identical parity with the coding subject picture to the position indicated by the zero vector to the block as the coding subject.