A variable compression ratio engine. The engine includes a piston disposed in a cylinder bore and constituting a combustion chamber, a variable compression ratio mechanism connected to the piston and causing a top dead center position of the piston to vary, an actuator connected to the variable compression ratio mechanism to actuate the variable compression ratio mechanism, and a controller connected to the actuator to control an engine state and the actuator. The controller performs operations including setting the compression ratio corresponding to a state of the engine, actuating the actuator so that the compression ratio is set, determining whether a state of the engine is either a state allowing actuation of the actuator, or a state limiting actuation of the actuator, and limiting actuation of the actuator in the state limiting actuation of the actuator.