A semiconductor dynamic RAM for image processing, according to the present invention, comprises a VRAM having logical operation function of performing a predetermined logical operation of an input data signal and an output from a selected one of memory cells and rewriting the selected memory cell with a result of the operation. It includes a write read control circuit including a level determination circuit for determining a level of the input signal under control of the logical operation enable signal. Based on the result of determination of the logical level of the input signal, either write of the input signal to the selected memory cell or refresh of information stored in the selected cell is performed to effectively perform the logical operation.