PURPOSE: To simplify the positioning of upper and lower containers, by providing a latch which may be retracted by the operation of a handle and which is adapted to be attached to a receiving fixture of the upper container.

CONSTITUTION: A fixture 1 consisting of an insertion shaft part 5 having an inclined surface, a latch 7, a handle 14 for retracting the latch 7, a flange 2, an inclined surface 3 and an engaging piece 4, is used between receiving fixtures of upper and lower containers. The engaging piece 4 is inserted and secured in the receiving fixture 30 of the upper container 31' to attach the fixture 1. Thereafter, the insertion shaft part 5 is inserted in the receiving fixture 30 of the lower container 31' so that the upper and lower containers are surely fixed together by means of the latch 7.