NOVELTY - The structure support tool (4) has a fixing base (22) having a main plate through which a slide hole is formed and side plates respectively bent in similar orientations at sides of main plate. A flange is bent outward at one side of side plates. A movable portion is capable of moving along the slide hole of main plate so as to engage with the inner faces of respective side plates of the fixing base. A coupling shaft (21) is connected to the movable portion through the slide hole of main plate.    USE - Structure support tool of solar cell module system, for supporting structure e.g. solar cell module on roof rafter.    ADVANTAGE - The solar cell module is supported firmly in balanced manner while reducing number of support positions of the solar cell module easily.    DETAILED DESCRIPTION - The structure support tool comprises a washer portion (24) overlapped on a main plate of fixing base in a freely movable manner. The washer portion has a hole for guiding the structure coupling portion to the slide hole of main plate. A pair of catches is inserted to the slide hole of main plate to hold the movable portion. The holding plates in washer portion are arranged for respectively holding the outer faces of side plates of the fixing base. The inner shape of the side plates of fixing base and outer shape of movable portion are engaged with each other, and the movable portion is held so as not to be detached from space between the side plates. The side plates of the fixing base are bent at the sides of main plate of the fixing base such that a distance between the side plates is shorter near the flange of fixing base. The movable portion is in contact and engaged with the inner faces of the side plates of fixing base. The main plate of the movable portion is overlapped with the main plate of fixing base, and the side plates of movable portion are in orthogonal contact and engaged with the side plates of fixing base. Several holes are formed only in a half region obtained by equally dividing each flange of the fixing base into two along a segment orthogonal to the slide hole of the main plate of fixing base. A male screw is formed at one end portion of the coupling shaft and fastened via the slide hole of the main plate of the fixing base into a screw hole of the movable portion, such that the coupling shaft is connected to the movable portion. The coupling shaft has a coupling portion main unit and a bolt connecting the coupling portion main unit to the movable portion. The bolt is fastened via a hole of the coupling portion main unit and slide hole of main plate into a screw hole of the movable portion such that bolt and main unit are connected to movable portion. INDEPENDENT CLAIMS are included for the following:    (1) structure installation method which involves placing and fixing each flange of the fixing base of structure support tool on a roof rafter. The movable portion is moved between the side plates of fixing base along the slide hole of fixing base. A hole is formed through a roof tile (5), and the roof tile is formed on the rafter such that the hole of roof tile overlaps the movable portion. The coupling shaft of structure support tool is connected via the hole of the roof tile and slide hole of the fixing base to the movable portion; and    (2) solar cell module system.    DESCRIPTION OF DRAWING(S) - The drawing shows a plan view of the structure support tool.    Structure support tool (2)    Roof tile (5)    Coupling shaft (21)    Fixing base (22)    Washer portion (24)