The present disclosure relates to an image processing device and an image processing method capable of reducing a processing burden required at the time of generating a stream. A file generating unit sets a startcode and filler data for a file including a bitstream acquired by coding an image and performs control of the setting of the startcode and the filler data such that the startcode and the filler data that are set configure a file with a characteristic of a parameter managing a decoder buffer being maintained in media data of the file. The present disclosure, for example, can be applied to an image processing device.