An object of the present invention is to provide a semiconductor device capable of diagnosing disconnection of a signal line that transmits a command signal in an inspection process even if the command signal is assumed not to be transmitted in the inspection process. A semiconductor device according to the present invention includes a first semiconductor integrated circuit and a control circuit, the control circuit includes a means for controlling a signal line in response to a response signal from the first semiconductor integrated circuit, and the control circuit further includes a means for controlling the signal line regardless of a signal from the first semiconductor integrated circuit.