A method of producing an electronic device includes a holding of a circuit board and a decoration sheet in a cavity of a mold, and a filling and solidifying of thermosetting resin in the cavity. A casing is molded by the solidified thermosetting resin so as to seal electronic parts and a first face of the circuit board having the electronic parts. Further, the decoration sheet is integrated with the casing by the solidified thermosetting resin. An outer surface of the casing is defined by a second face of the circuit board opposite from the first face and the decoration sheet.