A gate circuit used for controlling an interface circuit in a microcomputer system, including a first-stage gate circuit, a second-stage gate circuit, and a control device connected between the first-stage gate circuit and the second-stage gate circuit. The first-stage gate circuit outputs an inverted strobe signal to the interface circuit, and the second-stage gate circuit outputs a non-inverted strobe signal to the interface circuit. Although there is a time lag in the changeover timing of these strobe signals, this time lag is reduced by connected the diode between the first-stage gate circuit and the second-stage gate circuit.