PURPOSE: To prevent the stripping and slippage of a cap at the time of press- fitting and ensure the sealing property to a socket by mutually inserting and holding a hard sleeve into the cap at the time of installing the cap of an ignition cable device to the socket part of a high voltage generator.

CONSTITUTION: An ignition cable 1 having a silicon rubber sheath is inserted through a sleeve 7 formed from a glass fiber reinforced phenol resin, a stainless steel cable terminal 2 is then mounted on the terminal of the ignition cable 1, and the sleeve 7 is shifted to the position of the cable terminal 2 and fixed. Thereafter, it is mounted in a cap molding mold die 2, a liquefied silicon rubber is injected thereto to integrally mold a cap 3. Thus, no abnormally installing state is never caused at the time of press-fitting the cap to a socket part 5, the mounting is facilitate, and the quality is also uniformed.