To provide a cleaning filter for a lubricating oil improved in lubricating characteristic at a sliding part by sticking a detergent-dispersant on a porous body and removing foreign matters surrounded in the detergent-dispersant from a circulating lubricating oil.

The cleaning filter for the lubricating oil is composed of a filter cylindrical body 1 provided with an inlet 12 introducing the circulating lubricating oil and an outlet 13 sending out a cleaned lubricating oil, a filter element 2 arranged at an upstream side part in the filter cylindrical body 1 and capturing a contaminated substance such as trash and metal powder incorporated in the lubricating oil, a ceramic porous body 3 arranged at a downstream side part of the filter element 2 in the filter cylindrical body 1 and the detergent- dispersant impregnated in the ceramic porous body 3. The ceramic porous body 3 is produced from Si3N4 and the detergent-dispersant is stuck on a wall surface of the ceramic porous body 3.