PURPOSE: To make it unnecessary to use fastening means for the top frame by forming a front top frame which is connected with the loose end of a rear top frame in a manner of making the front top frame freely swung only upward and by providing a fastening means, whose upper part of a front frame erected and swung can be freely fitted from the outside, on the part from the front edge of the front top frame to the front side.

CONSTITUTION: A front top frame 15B is formed, which is connected with the loose end of a rear top frame 15A in a manner of being allowed to be freely swung with a coil-shaped hinge 19 for the joint. The front top frame 15B can be freely swung only upward relative to a rear top frame 15A. From the front edge of the front top frame 15B forward fastening means 20 are provided, which can be freely fitted from outside over the upper part of an upper front frame 4B of front frame 4 after swinging of the upper front frame from the erect position. The fastening means 20 and the upper front frame 4B are connected to two lateral frames 10, 12 by fastening by fastening devices 13, 14. Therefore, it becomes unnecessary to use a fastening device for the top frames 15 and the handling of the container is simplified.