To provide a solar panel holding tool that has a simple structure, is excellent in workability and is strong against pressure from below as well as from above.

A method in which a panel is nipped by U-shaped and box-shaped guide rails from both sides is adopted in lieu of a conventional method in which the panel is mounted on an acceptance body and is fixed thereto by screws. One end of the guide rail is opened as an insertion port of a panel frame, and the other end is closed such that the panel frame inserted abuts against the other end closed and is locked and forms a front wall portion. Further, rear surfaces of the respective guide rails are bonded together for each pair of two guide rails, and H-shaped compound rails are formed. Fastening members are individually installed in the vicinities of both end potions of the compound rails. The respective compound rails with the insertion ports positioned obliquely above are arranged side by side in parallel while maintaining the same interval as a lateral width of the panel and are assembled to two upper/lower supporting columns installed horizontal to the ground by the fastening members. The solar panel is inserted from the insertion port, slides and descends, straightly reaches the front wall portion, abuts thereagainst and is locked.