To reduce connection defects by suppressing corrosion of a connection terminal portion of an electric conductor and a conductive bush since a conventional ignition coil for internal combustion engine has a conductive metal bush and an electric conductor, connected to the conductive bush, electrically connected to each other on an upper surface of the conductive bush positioned outside a coil case and then an interface of the electric connection portion is in the atmosphere, so there is a risk of a connection defect due to corrosion of the connection terminal portion of the electric conductor and the conductive bush.

The coil case is formed by molding the electric connection portion of the electric conductor, connecting the conductive bush coming into contact with an electric ground potential portion to a power supply ground terminal of a connector provided in the coil case, of resin in one body inside a resin molding forming the coil case.