Variable compression ratio device for internal combustion engine

A variable compression ratio device for an internal combustion engine includes: a connecting rod, having a small end and a large end, wherein a support hole formed at the small end is pivotally supported by a support shaft of a piston that reciprocates in a cylinder, and a support hole formed at the large end is pivotally supported by a support shaft of a crankshaft; an eccentric sleeve that is rotatably installed between the support hole of the small end or the support hole of the large end and the support shaft, and displaces a center axis of the support hole of the small end or a center axis of the support hole of the large end with respect to a center axis the support shaft; and an actuator that drives and rotates the eccentric sleeve.