An image encoding apparatus which encodes picture data is provided. The apparatus comprises an encoding unit configured to encode a picture to be encoded; a decoding unit configured to decode the encoded picture; an SN ratio calculation unit configured to calculate an SN ratio using the picture to be encoded and a decoding result of the decoding unit; a setting unit configured to set a target SN ratio serving as an index of the SN ratio; a bitrate control unit configured to control a bitrate of the picture to be encoded based on the target SN ratio; and a motion detection unit configured to detect motion information between the picture to be encoded and another picture, wherein the bitrate control unit controls the bitrate based on the motion information, and a difference between the SN ratio and the target SN ratio.