Oil supply device

The present invention provides an oil supply device, which is a capless oil supply device that can suppress the violent ejection of vapor or oil from the oil supply port when the oil supply port is opened in a state where the internal pressure of the oil tank is high. A main flap valve (14) is provided in the oil supply pipe (4), and the main flap valve (14) is forced to close the oil supply passage (5) to airtightly close the oil supply passage (5). The recirculation pipe (10) connected to the upper part of the oil tank (2) is connected to a connection port (4a) formed on the oil supply pipe(4) on the oil tank (2) side of the main flap valve (14). The main flap valve (14) in the oil supply passage (5) is provided with a check flap valve (22) on the oil tank (2) side. The check flap valve(22) is forced toward the open position of the open oil supply passage (5), and is driven toward the closed position by the pressure of the fluid flowing from the recirculation pipe (10) to the oil supply pipe (4). As a resul