PURPOSE: To obviate conventional spring and prolng the operation life and reduce the cost by operating magnetic replusion between a sticklike member and ringlike members at an outer pipe portion into whose inside the stick member is inserted, conducting energization by this so that a valve body may be closed at all times.

CONSTITUTION: This check valve 20F is interveniently furnished at a passage which supplies fuel to the sub chamber of a sub chamber type thin combustion gas engine. In this instance, a sticklike member 10 is inserted into the inside of the outer pipe portion 24 of the check valve 20F, and a valve body 13 is provided at one end portion of the sticklike member 10. Meanwhile, a valve seat 12 is formed at one end portion of the outer pipe portion 24 which is on a side to come into contact with the valve body 13, and a ringlike member 28 consisting of a magnet having the quality of high temperature durability is provided at the other end portion of the sticklike member 10. In addition, a similar ringlike member 26 is provided at the other end portion of the outer pipe portion 24. Respective magnetic fields are arranged so that both ringlike members 26, 28 may repel each other. As a result, by operating required force U to the sticklike member 10, and by this, the valve body 13 is seated at the valve seat 12.