An objective of the invention is to provide an adsorbent allowing purification of a blood coagulation factor or a cell adhesion factor under mild conditions, according to simple procedures, and at a low cost and safely while having a high affinity and a high resistance to deterioration, and a method for purifying the blood coagulation factor or the cell adhesion factor; a solution is to apply a polypeptide having peptide fragments represented by formula (1) as the adsorbent for the blood coagulation factor or the cell adhesion factor, and to purify the blood coagulation factor or the cell adhesion factor using the adsorbent: -(Pro-Hyp-Gly)n- Wherein, in formula (1), n is an integer from 2 to 9,000.