PURPOSE: To easily drain the engine oil of an automobile together with the metallic powder accumulated at the bottom by screwing an oil drain plug which is usually in the shut-off condition into an oil pan, and pressing a shut-off valve from the outside to open it.

CONSTITUTION: An oil drain plug 1 is screwed in and fitted to an oil drain hole of an oil pan 102. A cap of the oil drain plug 1 is removed, and a shut-off valve opening tool 4 is fitted. This shut-off valve opening tool 4 is provided with a valve element pressing rod part 44, and it separates a ball 133 of the shut-off valve in the oil drain plug 1 from a valve seat 132 against the energizing force of a spring 134 when it is fitted, and the shut-off valve is opened by assembling the shut-off valve opening tool 4. The oil flowing in a valve chamber from an inner opening 123 flows out in a cylindrical passage 114 through the ball 133 separated from the valve seat 132, and vacuum-sucked through a tube connecting cylindrical part 412.