A roof box includes: a body; lock mechanisms in both sides of the body to engage and fasten a storage portion and an openable/closable cover; unfastening mechanisms in each of the lock mechanisms provided in both sides of the body to release the engagement and fastening; opening/closing means to open or close the openable/closable cover with respect to any one of the lock mechanisms when the engagement and fastening of the other lock mechanism is released; a manipulation means to transmit an opening/closing operation signal for selecting the lock mechanisms for releasing the engagement and fastening and opening or closing the openable/closable cover using the opening/closing means; and a control means to receive the opening/closing operation signal from the manipulation means, output an engagement release signal to the selected lock mechanism, and output an opening/closing signal for releasing the openable/closable cover to the opening/closing means after the engagement is released.