Disclosed is a semiconductor device comprising: a signal selecting circuit for receiving, at first and second inputs thereof, respectively, a first signal output from a first initial-stage circuit that receives a data strobe signal from a first terminal, which is an input/output terminal, and a second signal output from a second initial-stage circuit that receives a data mask signal from a second terminal, which is an input terminal, and based upon a control signal that is supplied thereto, outputting the first and second signals from first and second outputs or interchanging the first and second signals and outputting the interchanged first and second signals from the second and first outputs; a buffer circuit for receiving an output signal from a third initial-stage circuit that receives a data signal from a data terminal; and a data latch circuit for latching a signal from the buffer circuit. The signal from the first output of the signal selecting circuit is supplied to the data latch circuit as a latch timing signal.