Charging port structure of vehicle

A charging port structure of a vehicle according to the present disclosure includes: an opening portion (3) formed on an outer panel (2) of the vehicle and openable and closable by a lid (11); an inlet (9) which is fixed in a state of being inserted from the inside of the vehicle into an opening (16) formed in the inner plate (6) facing the outer plate (2), and which is provided facing the opening (3); a charging port holder (4) which is fitted into the opening (3) from the outside of the vehicle, is vertically provided in a cylindrical shape from the outer plate (2) toward the inner plate (6), forms the inner peripheral wall of the charging port, and surrounds a connection terminal (12) of the inlet (9); a cylindrical rib (23) which is fitted into the opening (16) together with the inlet (9), and which is provided upright toward the outer plate (2) side so as to surround the periphery of the connection terminal (12) of the inlet (9); and a first seal (5) that is provided at the inner plate (6)-side end of th