To provide a cardboard box assembly apparatus capable of assembling a recycled or new cardboard box by means of a simple configuration, and of reliably assembling the corrugated cardboard box.

In the cardboard box assembly apparatus 100, some of panels 901 to 904 of the cardboard box 900 are locked by locking members 301 to 304 and others of the panels 901 to 904 of the cardboard box 900 begin to be detruded by interleaved folding mechanisms 401 to 404. Subsequently, the locking members 301 to 304 are moved in the vertical upward direction by mover devices 501 to 504, and others of the panels 901 to 904 of the cardboard box 900 are further detruded by the interleaved folding mechanisms 401 to 404.