PURPOSE: To reduce contamination of substance other than a measuring object being a target into a solution to be measured so as to conduct measurement with high reliability and reduce nonspecific adsorption of a free state marker substance to the periphery of a detection part so as to conduct measurement with high accuracy in an immunological analyzing method and its device.

CONSTITUTION: A reaction mixed solution, containing a complex wherein a solid phase and marker substance are bonded to a measuring object in a sample produced by an antigen/antibody reaction, is introduced to a suction nozzle 5. In the suction nozzle 5, the solid phase in the reaction mixed solution is magnetically captured, then a buffering solution for separation is made to flow in the suction nozzle 5 in the direction reverse to a flow cell when viewed from the suction nozzle 5 to discharge free state substance without passing through the flow cell 24, and the solid phase is introduced into the flow cell 24.