The present invention provides a medical instrument exhibiting excellent lubricity and durability (maintenance of lubrication). The present invention relates to a medical instrument having: a substrate layer； an adhesive layer which is formed on at least a portion of the substrate layer and which includes a hydrophilic copolymer including constituent units derived from a polymerizable monomer (A) having a sulfobetaine structure, constituent units derived from a polymerizable monomer (B) having at least one group selected from the group consisting of a sulfonic acid group (-SO
