Abstract: A solar cell having a semiconductor layer of a chalcopyrite structure as a light absorption layer and using a flexible film as a substrate, breakdown and peeling caused to the semiconductor layer of the chalcopyrite structure due to warp of the flexible film upon heat treatment is prevented. To realize this, a poly(phenylene terephthalmide) film having a coefficient of heat expansion of 5.0×10−6/° C. is used as a substrate (1). After a Ti reinforcing layer (6) is disposed on the entire back surface of this substrate (1), a first electrode layer (2) is disposed on the front surface of this substrate (1), and a p-type semiconductor layer (3) of a chalcopyrite structure is formed as a light absorption layer on the surface of the first electrode layer (2).