PROBLEM TO BE SOLVED: To provide a medical valve with a new structure capable of securely supporting an outer peripheral part of a disk-shaped elastic valve body to a housing to prevent the elastic valve body from falling off inwardly.SOLUTION: A medical valve 10 includes an elastic valve body 16 and an opening member 12. The elastic valve body 16 has an inner annular groove 88 and an outer annular groove 86, the grooves extending on inner and outer surfaces of an outer peripheral part in a circumferential direction. In addition, the elastic valve body 16 has a cylindrical support part 82 on an outer peripheral side of an annular connection part 84 positioned between bottoms of the inner annular groove 88 and the outer annular groove 86, the cylindrical support part 82 inwardly and outwardly projecting in an axial direction. The opening member 12 that supports the cylindrical support part 82 has an inner engaging claw 74 and an outer engaging claw 56, the engaging claws being configured to be fitted into the inner annular groove 88 and the outer annular groove 86 of the elastic valve body 16 to engage therewith. The cylindrical support part 82 has an engaging recess 92 opening at an end in the axial direction. The engaging recess 92 is engaged with an engaging protrusion 78 inserted thereinto, the engaging protrusion 78 being formed on the opening member 12.