PURPOSE: To provide a push-pull probe with a filter for collecting a biological substance ranged from low molecular weight to high molecular weight effectively.

CONSTITUTION: This push-pull probe is formed in such a manner that a tip part 4 of a filter tube 3 which is composed of a membrane substance having a distributed pore of 0.1-0.2μm in diameter and whose inner diameter is formed as 1500-2000 times as pore diameter is sealed, and an inlet conduit tube 5 which has a tip opening behind the tip is inserted into this filter tube 3, and an outlet conduit tube 6 communicating with a space in the filter tube 3 on the outside of the inlet conduit tube 5 is formed. An aspirating means for exhausting substantially the same or slightly more than the transmitted fluid amount is connected to the outlet conduit tube 6 as well as fluid feed means connecting with the inlet conduit tube 5.