To obtain a manufacturing method for a chalcopyrite-based solar battery wherein any complex large equipment is not required and the chalcopyrite layer of an excellent quality can be formed by a small number of manufacturing processes in a comparably short time with a low cost.

The chalcopyrite-based solar battery is formed by first and second processes. In the first process, a copper substrate 11 having a formed copper film on its surface is so contacted with a fused In or the mixture of the fused In and a fused Ga as to form a CuIn reaction layer or a CuInGa reaction layer on the surface of the copper substrate 11. In the second process, the CuIn layer or the CuInGa layer formed on the surface of the copper substrate 11 is so contacted with one of a fused Se and the mixture of the fused Se and a fused S as to form the chalcopyrite layer 13 on the surface of the copper substrate 11.