Gas combustion type driving tool

An ignition plug of a gas combustion type driving tool comprising:

• a center electrode;
• and
• a plurality of stagnation parts provided between an exposed base portion of the center electrode and a leading end thereof,
• wherein each stagnation part is formed by an annular step part or an annular protrusion, each stagnation part having a diameter greater than a diameter of the leading end, and the most distal stagnation part terminating axially short of the leading end.

A gas combustion type driving tool comprising:

• a driving cylinder disposed in a tool body;
• a driving piston provided in the driving cylinder slidably in an up-down direction;
• a movable sleeve provided on an upper part of the driving cylinder;
• a cylinder head provided above the driving cylinder;
• a combustion chamber which is opened and closed by moving the movable sleeve up and down to bring and separate the movable sleeve into contact with and from the driving cylinder and the cylinder head thereabove;
• an ignition plug disposed in the cylinder head;
• and
• a stagnation part provided between an exposed base portion of a center electrode of the ignition plug which is exposed to the combustion chamber and a leading end of the center electrode, the stagnation part having a diameter greater than a diameter of the leading end, and the stagnation part terminating axially short of the leading end,
• wherein an upper surface of the stagnation part is exposed to the combustion chamber.