A variable compression ratio apparatus may include a connecting rod rotatably connected to the piston so as to receive the combustion force therefrom, a pin link mounted to the crankshaft and rotatably connected to the connecting rod so as to receive the combustion force from the connecting rod and rotate the crankshaft, a connecting link rotatably coupled to the pin link and changing a rotation trace of the pin link with respect to a rotation axis of the crankshaft, an eccentric camshaft provided with first and second shaft portions eccentric from each other and configured to rotate by a predetermined angle according to a driving condition of the engine, a sub control link rotatably connected to the eccentric camshaft about the first shaft portion and rotatably connected to the connecting link, and a main control link rotatably connected to the eccentric camshaft about the second shaft portion and rotatably connected to the connecting link.