This lubricating device 1 is equipped with an oil pan 2 that stores therein lubricating oil, a micro bubble generator 4 that mixes the lubricating oil with air to produce micro bubbles and supplies the lubricating oil in the oil pan 2 with the micro bubbles, and an oil pump 3 that pressurizes the lubricating oil in the oil pan 2 to supply the micro bubble generator 4 therewith. Further, in this lubricating device 1, the micro bubble generator 4 has an air inlet portion 431 disposed inside the oil pan 2 at a predetermined position with respect to an oil surface height (oil level) of the lubricating oil in the oil pan 2.