In a memory card which includes a memory chip and a controller connected to the memory chip for the control of transferring a data from outside, the controller is provided with a buffer in which data is temporarily stored. In a first operation mode, the controller clears the data stored in the buffer after the data in the buffer is transferred to the memory chip. In a second operation mode, the controller does not clear the data stored in the buffer even after the data in the buffer is transferred to the memory chip. By the use of these modes, it becomes possible to write the data obtained by means of external transfer into the memory chip repeatedly for a plurality of times by means of internal transfer. Thus, it becomes unnecessary to repeat external transfer and internal transfer every time.