A spark ignition type engine enabling engine startability to be favorable is provided. The spark ignition type engine includes a main intake-air passage; a throttle valve of the main intake-air passage; a bypass intake-air passage bypassing the throttle valve; an ISC valve of the bypass intake-air passage; and an electronic control device that controls an engine speed by adjusting an opening degree of the ISC valve, in which when the engine is started, cranking is performed at a cranking opening degree at which the ISC valve is narrowed by a predetermined amount from a fully opened state by control of the electronic control device, so that an intake-air negative pressure is generated on an intake-air downstream side of the ISC valve.