An image encoding apparatus for encoding image data, the image encoding apparatus comprising: a syntax element generating section for generating syntax elements from the image data; an intermediate data generating section for generating intermediate data by binarizing the syntax elements; a plurality of entropy encoding sections for generating bit streams by entropy-encoding the intermediate data which are the binarized syntax elements; a multiplexing section for multiplexing a plurality of the encoded bit streams into one bit stream; and an encoding control section for writing the intermediate data which are the binarized syntax elements output from the intermediate data generating section to a memory, reading the intermediate data from the memory, and supplying the intermediate data to any of the entropy encoding sections, wherein the encoding control section determines an entropy encoding section that performs an entropy encoding process by a frame in accordance with processing status of each of the entropy encoding sections, reads the intermediate data which are the binarized syntax elements of a corresponding frame from the memory, and supplies the intermediate data of the corresponding frame to the determined entropy encoding section, the determined entropy encoding section entropy-encodes all the intermediate data which are the binarized syntax elements of the corresponding frame, and other entropy encoding section does not entropy-encode the intermediate data of the frame concerned, wherein the encoding section generates multiplexing control information related to frames output to the entropy encoding sections (105, 106) and notifies the multiplexing control information to the multiplexing section, wherein the multiplexing control information includes: encoding order information, indicating how many frames that were input had preceded before the frame to be output to the entropy encoding sections (105, 106) next, and encoding assignment information indicating which of the entropy encoding sections (105, 106) will process the frame to be output next; and wherein the multiplexing section writes the bit streams to the memory in accordance with the multiplexing control information received from the encoding control section while distinguishing the bit streams in frame units, and reads the bit streams, which are written in the memory separately from each other, in frame units in order, and then converts the bit streams into a bit stream in the original order. a syntax element generating section for generating syntax elements from the image data; an intermediate data generating section for generating intermediate data by binarizing the syntax elements; a plurality of entropy encoding sections for generating bit streams by entropy-encoding the intermediate data which are the binarized syntax elements; a multiplexing section for multiplexing a plurality of the encoded bit streams into one bit stream; and an encoding control section for writing the intermediate data which are the binarized syntax elements output from the intermediate data generating section to a memory, reading the intermediate data from the memory, and supplying the intermediate data to any of the entropy encoding sections, wherein the encoding control section determines an entropy encoding section that performs an entropy encoding process by a frame in accordance with processing status of each of the entropy encoding sections, reads the intermediate data which are the binarized syntax elements of a corresponding frame from the memory, and supplies the intermediate data of the corresponding frame to the determined entropy encoding section, the determined entropy encoding section entropy-encodes all the intermediate data which are the binarized syntax elements of the corresponding frame, and other entropy encoding section does not entropy-encode the intermediate data of the frame concerned, wherein the encoding section generates multiplexing control information related to frames output to the entropy encoding sections (105, 106) and notifies the multiplexing control information to the multiplexing section, wherein the multiplexing control information includes: encoding order information, indicating how many frames that were input had preceded before the frame to be output to the entropy encoding sections (105, 106) next, and encoding assignment information indicating which of the entropy encoding sections (105, 106) will process the frame to be output next; and encoding order information, indicating how many frames that were input had preceded before the frame to be output to the entropy encoding sections (105, 106) next, and encoding assignment information indicating which of the entropy encoding sections (105, 106) will process the frame to be output next; and wherein the multiplexing section writes the bit streams to the memory in accordance with the multiplexing control information received from the encoding control section while distinguishing the bit streams in frame units, and reads the bit streams, which are written in the memory separately from each other, in frame units in order, and then converts the bit streams into a bit stream in the original order.