The present invention provides a technique capable of simplifying a layout structure of a semiconductor device having a semiconductor memory section in which an input port and an output port are separated from each other, and which includes a bypass function. In a semiconductor memory device to be used as a semiconductor memory section of the semiconductor device, in a bypass mode, an output buffer outputs input data transmitted through a bypass line, extending from an input buffer circuit to the output buffer circuit, to an output port. In the layout structure of the semiconductor memory device, in plan view, a memory cell array is arranged between the input buffer circuit and the output buffer circuit, and a bypass line is arranged through between the memory cell arrays.