Patent ID: 8851915

Claim:
A plug cap comprising: an electrical connection portion that electrically connects a spark plug to a plug cord, the spark plug being connected to one end of the electrical connection portion and the plug cord being connected to an opposite end of the electrical connection portion; a terminal body that is made of a resin, is provided on an outer periphery of the electrical connection portion, and includes a one end-side insertion portion formed at one end of the terminal body and into which the spark plug is inserted, and an opposite end-side insertion portion formed at an opposite end of the terminal body and into which the plug cord is inserted, at least the one end-side insertion portion and the opposite end-side insertion portion being formed in a cylindrical shape; and a cylindrical rubber member mounted on at least one of one end portion and an opposite end portion of the terminal body and into which the spark plug or the plug cord is inserted, wherein the rubber member includes: an inner cylindrical portion inserted into a one end-side insertion portion or the opposite end-side insertion portion of the terminal body, an outer cylindrical portion positioned close to an outer periphery of the inner cylindrical portion and disposed with the terminal body interposed between the outer cylindrical portion and the inner cylindrical portion, and a connecting portion that connects a lower-most portion of the outer cylindrical portion to a portion of the inner cylindrical portion that extends below the lower-most portion of the outer cylindrical portion, and the inner cylindrical portion includes: at least one annular protrusion extending radially outward from the inner cylindrical portion and coming into contact with an inner peripheral surface of the terminal body.