PURPOSE: To provide an oil quantity detection device capable of constantly detect proper oil quantity even when a vehicle is inclined and oil level in an oil pan varies concerning the oil quantity detection device of engine oil of the vehicle.

CONSTITUTION: This oil quantity detection device is constituted by furnishing a float 1 to detect oil level in an oil pan and a float guide 8 to engage with the float 1 free to move, supporting one end of the float guide 8 by a support arm 10 free to oscillate and installing a dead weight 9 on the other end of the float guide 8 so that even when the oil level 2 of the oil pan varies, the float guide 8 constantly rests at a position where its shaft center line M-M comes to be vertical against the oil level 2 regardless of inclination of the oil pan.