The present invention provides a testing device testing a multi-cylinder engine including a plurality of ports including an intake port and an exhaust port in a pseudo driving state. The device includes a plurality of pressure inspection units and at least one opening/closing mechanism. Each of the plurality of pressure inspection units includes a pipeline connected to one of the plurality of ports, a sensor for detecting a pressure in the pipeline and a valve for opening/closing the pipeline. The opening/closing mechanism includes one actuator and a transmission mechanism connected to the actuator and transmitting a driving force of the actuator to an operation unit of each of the plurality of valves to open and close the plurality of valves.