A medical instrument is disclosed having a structure capable of preventing liquid circulation between an inner layer side and an outer layer side of a peripheral wall portion. The medical instrument includes a main body portion in which a center hole and a radially outward space are partitioned by a tubular peripheral wall portion. The peripheral wall portion includes at least a first layer on which a hydrophilic member, in which a hydrophilic coating is formed on a first base portion, is disposed and a second layer on which a hydrophobic member, in which a hydrophobic coating is formed on a second base portion, is disposed. The peripheral wall portion is configured by the first layer and the second layer being stacked along a radial direction. As a result of swelling of the hydrophilic coating, the adjacent hydrophilic members come into contact with each other.
