To provide an evaluation method to perform a biocompatibility evaluation of body liquid treatment column materials for the second column onwards accurately, promptly, and at low cost when two or more body liquid treatment columns are used, and especially, when two or more columns are connected in series and used simultaneously.

It is a biocompatibility evaluation method for the body liquid treatment column materials, which is characterized by performing a biocompatibility evaluation of a body liquid treatment column (B) material using a body liquid brought into contact with a body liquid treatment column (A) material.