An apparatus for locking a trunk of a vehicle includes a trunk lid, a driving unit for locking disposed on the trunk lid, a driven unit for locking disposed on the trunk lid, a connecting rod connecting the driven unit to the driving unit, and a support unit supporting the connecting rod to the trunk lid. The support unit includes a guider disposed on the trunk lid and a moving member disposed on the connecting rod and movably disposed on the guider. The driving unit includes a rotatable first lever attached to one end of the connecting rod. The driven unit includes a rotatable second lever attached to another end of the connecting rod.