PROBLEM TO BE SOLVED: To provide a photovoltaic power generator which is excellent in water tightness for performing simple and quick construction.SOLUTION: A structural material 3 is provided with: a structural material 3; a plate-shaped photovoltaic power generation unit A arranged in a frame body 2 configured of both vertical frames, a horizontal lower-water frame and a horizontal upper-water frame; and a longitudinal vertical gutter material 4 formed with a mounting protrusion section 42 at almost the center of the vertical gutter-shaped section 41. The vertical frame is provided with vertical frame gutter-shaped sections 213a and 223a, and the horizontal lower-water frame is provided with a horizontal section 233b outside from the middle, and the horizontal upper-water frame is provided with a horizontal gutter-shaped section 243c. A plurality of vertical gutter materials 4 are fixed so as to face to a tilting direction between the plurality of structural materials 3 arranged in parallel, and adjacent vertical frames 22 and 22 of the photovoltaic power generation unit are placed and fixed to the vertical gutter member 4. The horizontal lower-water frame and the horizontal upper-water frame of the photovoltaic power generation unit A are arranged so as to face each other in the same direction as the longitudinal direction of the vertical gutter member 4. The outer edge of the horizontal section 233b is abutted on the middle of horizontal water upper frame, and arranged in the upper part in the horizontal gutter section 243c, and the both ends of the longitudinal direction are arranged in the vertical gutter section 41.