Abstract: A water protecting cap used for a distributor, which is to distribute ignition voltage in an internal combustion engine, with the object of preventing water from coming into the interior of a casing of the distributor through a ventilation opening formed in the casing. The cap is composed of a body portion to be crowned on a tower portion embracing the ventilation opening therein and a tongue portion integrally formed with the former. Between the body portion and the tongue portion a sheltered space is confined, which is protected from water spray which might come to the inside of the engine room of a vehicle. A ventilation passage formed through the cap body portion for being communicated to the ventilation opening is opened at the other end thereof at a position innermostly located in the sheltered space.