A problem that the present invention is to solve is to provide a pellet-shaped composition for medical use mainly comprising a polyvinyl chloride resin and exhibiting antithrombotic property when merely being molded. The present invention is a pellet-shaped composition for medical use which comprises 1 to 120 part(s) by weight of a plasticizer and 0.1 to 5 part (s) by weight of a (meth) acrylate copolymer containing a hydrophobic (meth)acrylate unit and a hydrophilic (meth)acrylate unit to 100 parts by weight of a polyvinyl chloride resin, wherein number-average molecular weight of the (meth)acrylate copolymer is 7,000 to 50,000.