Provided is an
ignition coil for an
internal combustion engine, the
ignition coil having high waterproof performance which prevents water from entering a plug hole and also having high
water discharge performance. A high-
voltage generation section (3) for generating a
high voltage is housed within a coil case (4). A plug hole seal (5) is provided in order to close the opening of a plug hole (2) in which an ignition plug (21) is mounted. The
ignition coil is also provided with a space section (6) which is provided on the outer side of the high-
voltage generation section (3), and an air passage (9) through which air flows between the space section (6) and the plug hole (2). The lower surface of the space section (9) is open (the entire lower surface is open to facilitate die removal).