A variable compression ratio apparatus, which is provided to an engine rotating a crank shaft upon receiving combustion power of a mixture from a piston for changing a compression ratio of the mixture, may include a connecting rod transferring combustion power of the mixture received from the piston to the crankshaft, and including a small end rotatably connected with the piston and a large end forming a circular hole, a crank pin, an eccentric cam disposed to be concentrically rotatable in the hole of the large end, an eccentric link at which the eccentric cam is disposed at a first end, a variable link having a first end rotatably connected with a second end of the eccentric link, a control link having a first end rotatably connected with a second end of the variable link, and a control shaft controlled by a controller and rotated together with the control link.