When controlling the valve characteristics of an intake valve and changing the compression ratio, an upper variation limit compression ratio, which is the upper limit of the variation of compression ratio, is determined according to the actual valve characteristics of the intake valve characteristics control. The upper variation limit compression ratio is set to a valve at which the intake valve does not collide with the piston. When a target compression ratio corresponding to the operation state of the engine is larger than the upper variation limit compression ratio, the compression ratio is set to the upper variation limit compression ratio that is smaller than the target compression ratio. Thus, collision between the intake valve and the piston can be prevented while allowing the compression ratio to be increased up to the maximum compression ratio of the range where the collision does not occur.