To provide a manufacturing method of a solar cell protective sheet reducing occurrence of wrinkles during manufacturing a flexible solar cell module and during a long-term outdoor exposure of the solar cell module, while having an excellent adhesion between its protective layer and its sealing material layer.

A manufacturing method of a solar cell protective sheet having a sealing material layer made of a thermoplastic resin A and a protective layer made of a thermoplastic resin B comprises: a process of forming a multilayer film by extruding the thermoplastic resin A and the thermoplastic resin B from a die mounted to an extruder; and a process of bringing the multilayer film into a tight contact with a cooling roller. When the fusion point of the thermoplastic resin A is Tm°C, the fusion point of the thermoplastic resin B is (Tm+60)°C or above, the temperature of the resins right after they are extruded from the die is (Tm+160)°C or above, and the temperature of the multilayer film after the film is contacting the cooling roller is (Tm-30)°C or below, while a lip clearance of the die is equal to or more than 0.7 mm.