Abstract: An ignition coil for use in an internal combustion engine includes a coil assembly including a primary coil and a secondary coil, a lead terminal electrically connected to the secondary coil, a noise prevention resistor connected to a spark plug, and a case. An internal space of the case includes a first space holding the coil assembly and the lead terminal and a second space including the noise prevention resistor. The case includes a pair of guides protruding toward the first space. The lead terminal passes through a gap between the pair of guides and is in contact with an exposed surface of the noise prevention resistor. This can reduce deviation of the lead terminal. As a result, the secondary coil and the noise prevention resistor can be electrically connected to each other without intervention of a high-voltage terminal therebetween.