The invention provides a mold clamping apparatus. The mold clamping apparatus (10) includes a fixed platen (13), a mold clamping cylinder (15), a movable platen (18) moved by the mold clamping cylinder toward the fixed platen, and a mold opening/closing actuator (16) for moving the movable platen or the mold clamping cylinder. The mold clamping apparatus further includes a mold thickness adjustment cylinder (50) provided between the mold clamping cylinder and the movable platen, the mold thickness adjustment cylinder (50) being configured to generate an axial force larger than an axial force in an expanding direction of the mold opening/closing actuator and smaller than an axial force in a contracting direction of the mold clamping cylinder.