A solid-state imaging device producing method includes the steps of: applying a resist material onto a substrate in which a channel region is formed; forming a resist layer by exposure and development of the resist material using a mask, the resist layer having an opening and a thin-film portion, the mask having a first region through which light is transmitted and a second region through which a smaller quantity of light than that the light transmitted through the first region is transmitted; subjecting the substrate to ion implantation using the resist layer as a mask to form an impurity region; etching the substrate using the resist layer as a mask after the ion implantation to form an alignment mark; and forming an electrode on the impurity region and part of the channel region using the alignment mark as a reference.