A motion detector calculates a camera shake matrix H(t) applied for a coordinate conversion for a camera shake correction. At this time, the motion detector calculates a motion vector (MV) for each block obtained by dividing a frame, and excludes an object motion vector (MV-B) from the MV. In addition, when a camera shake matrix H_mv that represents a camera shake between the frames is not calculable based on the MV, the motion detector calculates and adjusts a camera shake matrix H_sensor that represents a camera shake in accordance with a motion of an image picker, and settles this matrix as the camera shake matrix H(t).