To provide an assembly box which is different from a conventional one, easily assembled, and disassembled in an easy and compact manner.

In a connection structure of side wall panels 2, a claw part 203 or a recessed part 204 provided in a lateral side part of an adjacent side wall panel 2 is inserted into a recessed part 204 or a claw part 203 provided on a lateral side part of a side wall panel 2 in an outwardly diagonal direction, and the adjacent side wall panel 2 is turned to a base 1 side and connected and fixed thereto about the connection part being the axis. Further, in the connection structure of the side wall panel 2 assembled last, claw parts 203 or recessed parts 204 formed in right and left lateral side parts of the last side wall panel 2 are inserted into the recessed parts 204 or the claw parts 203 provided on the lateral side parts of both adjacent side wall panels 2 from above, and slide down to the base 2 and are connected and fixed thereto.