To solve such problem that a conventional scramble method randomly accesses a macro block so that an image can not be recognized when compressing or extending image data; and transfers a command representing whether or not the data are compressed ones, and coordinate data indicating an access sequence of the macro block in advance when transferring the compressed data.

An image coding apparatus 1a includes a conversion table 9 for recording a rearrangement rule regarding code data for every restart marker; a coder 17 for coding the image in a JPEG format using the restart marker; and a scramble converter 10 for rearranging the code data output from the coder for the restart marker, based on the rearrangement rule of the conversion table 9.