PURPOSE: To enable a prefabricated structure having sealing property and thermal insulation, to be constructed in a short period, by placing thermal insulating material between steel panels on both surfaces, and by connecting the steel panels and adjacent panels freely to each other via connecting members fitted on channel members.

CONSTITUTION: Both the side edges of steel panels 25a are processed to be folded so that the rise sections 25d of channel members may be wound in from an external side, and are assembled by press-processing without welding or the like. Besides, with a door frame 10 consisting of end support material 11 and horizontal beam material 13, a door 20 fitted on the door frame 10, to be freely opened or closed, a side wall 30 erected on the rear side of the end support material 11, a rear wall 50 for connecting the rear end of the side wall 30, and a ceiling 60 for covering an upper side, a prefabricated structure is formed, and the door 20, the side wall 30, and the rear wall 50 are formed with thermal insulating panels 21, 31, 51. Besides, the door frame 10 is provided with intermediate support material 12, and on its rear side, a partition wall 40 reaching the rear wall 50 is erected, and a continuous type prefabricated-structure is formed, and the partition wall 40 is connected to a thermal insulating panel 41.