The valve unit includes: a body having a charging passage; a supply-side joint that connects a supply pipe; and a check valve that is disposed in the gas passage, and that inhibits gas from being discharged from the gas tank to the outside of the body. The check valve includes a check valve seat, a check valve element that comes into contact with or moves away from the check valve seat, and a positioning member that fixes the position of the check valve seat in the charging passage. The body has a fitting hole which is communicated with the charging passage and in which the supply-side joint and the positioning member are fitted. The positioning member is fitted in a second fitting hole so as to fix the position of the check valve seat even when the supply-side joint has not been fitted in a first fitting hole.