There are provided a buffer circuit buffers data between a synchronous circuit and an asynchronous circuit, and a control method therefor. There are also provided an interface circuit that controls data transfer between a synchronous memory circuit and the asynchronous circuit, and a control method therefor, which are used in the buffer circuit and the control method therefor. A data buffer circuit that is interposed between an image processing system and a main system includes a one-port RAM, a control signal generating section, an subsequent cycle address generating section, and a first selector. The first selector selectively outputs the present cycle address to an address of the one-port RAM when an access to the one-port RAM is a write access, and selectively outputs the subsequent cycle address to the address of the one-port RAM when the access to the one-port RAM is a read access.