To easily clean a feed oil filter arranged in an oil feeding port of a tank.

A locking part 25 is arranged inside the oil feeding port 22 of the fuel tank 19, and a flange 24 of the cylindrically formed feed oil filter 23, is locked on the locking part 25 of the oil feeding port 22. A gripping part 26 is arranged upward in the flange 24, and is formed so that a worker can take out the feed oil filter 23 to the outside of the oil feeding port 22 by gripping the gripping part 26.