The purpose of the present invention is to provide a biological component adhesion-suppressing material that is able to suppress adhesion of platelets and proteins even when coming into contact with blood, etc. The present invention comprises a substrate which is provided with a functional layer having, fixed on a surface thereof that comes into contact with a biological component, a polymer including a saturated aliphatic monocarboxylic acid vinyl ester unit, wherein: when compositional analysis is performed on the surface of the functional layer using a TOF-SIMS device, the number of carbon atoms in an aliphatic chain representing an ion signal detected for saturated aliphatic carboxylic acid is 2-20; and an XPS measurement taken of the surface of the functional layer shows a peak derived from an ester group.