PURPOSE: To effectively utilize lubrication oil in a heat insulation tank by reducing incurring of the friction loss of an oil pump.

CONSTITUTION: An oil pump 4, an oil cooler 5, a heat insulation tank 6, and an oil filter 7 are arranged, in the order, in a lubricating oil passage 3 through which lubricating oil is guided to the slide part of an engine 2. A pressure regulating valve 9 to keep a system pressure approximately at a constant value is arranged in a communication passage 8 to bypass the oil pump 4 and intercommunicate a heat insulation tank 6 and a lubricating oil passage 3. In a lubricating oil feeding device 1, since, when during the low temperature starting of the engine 2, the number of revolutions of the engine is high, the system pressure of the lubricating oil passage 3 is increased to a value higher than the set pressure of a pressure regulating valve 9, most of lubricating oil the heat of which is insulated in the heat insulation tank 6 is returned through the communication passage 8 to an upper stream lubricating oil passage 3 with the aid of the oil pump 4 and an amount of lubricating oil flowing from the heat insulation tank 6 to the engine 2 side is decreased to a very low value.