An entry support system includes: a first identification information acquisition unit which acquires first identification information of a first related person in a first predetermined relation with a registered user; a first related person authentication unit which determines whether or not an externally located person is the first related person when the externally located person is recognized by an externally located person recognition unit in a state where an internal user determined as the registered user by a registered user authentication unit is recognized by an internal user recognition unit; and an entry permission unit which executes entry permission processing for enabling entry of the externally located person to a closed space from an entrance, when the externally located person is determined as the first related person by the first related person authentication unit.