A method of manufacturing a solar cell module includes adhering a first silicone gel sheet to one surface of a transparent light receiving panel to be a sunlight incidence surface; adhering a second silicone gel sheet to one surface of a light non-receiving panel on the side opposite to the sunlight incidence surface; disposing a solar cell string on the first silicone gel sheet of the light receiving panel, and disposing butyl rubber in a picture frame-like shape along an outer peripheral portion of the first silicone gel sheet; and laying the light receiving panel and the non-receiving panel over each other with the silicone gel sheets on the inside, and pressing them at 100 to 150 DEG C. in vacuum to encapsulate the solar cell string with the silicone gel sheets and press bond the light receiving panel and the non-receiving panel to each other through the butyl rubber.