To provide an immunity substance sorbing device for treatment by using extractoporeal circulation so as to absorb and remove an immunosubstance from plasma easily, selectively, and effectively which has less nonspecific adsorp tion of fibrinogen, the XII factor, and high-molecular weight kininogen or the like.

An immunity substance sorbing device for a treatment by using extracorporeal circulation is formed in such a manner that a suspected antigen compound having from one to 9 of amino acids or amino acid derivatives is provided on a surface of a porous substance body, and a volume of more than 10l and less than 1000ml of sorbent whose globulin property value is from 0.2mg/ml and to 20 mg/ml are filled up in a container having an inlet and outlet of plasma.