A solar battery mounting structure including a solar battery module which frame includes a light transmissive plate member, an adhesive portion by which a lower surface of a side end portion of the light transmissive plate member is adhered to an adhesive surface of a vehicle body frame member, and a fixation portion which is fixed to a lower surface of the light transmissive plate member through a sealing material layer, and is fixed to a fixation surface of the vehicle body frame member facing the lower surface, a protrusion portion in contact with the lower surface of the light transmissive plate member through the sealing material layer is fainted in the fixation portion, and frame a step portion is formed between the adhesive surface and the fixation surface.