The present invention provides a method for manufacturing a solar cell module having photovoltaic elements in each of which a metal oxide layer made of a metal oxide forms an outermost surface part thereof at a light incident side, and a sealing resin layer formed on the metal oxide layer. The method includes the steps of providing water on a surface of the metal oxide layer, the water being chemically adsorbed thereto; irradiating the metal oxide layer with electromagnetic waves for a predetermined time so that the contact angle of the water on the surface of the metal oxide layer is 60.degree. or less, the electromagnetic waves having energy larger than the band gap of the metal oxide; and subsequently forming the sealing resin layer on the metal oxide layer.