A connector formed with at least one cavity for at least partly accommodating at least one respective terminal fitting, comprising: a connector housing formed such that an opening is formed in at least one side surface to expose the cavity over the substantially entire length and the terminal fitting can be at least partly accommodated into the cavity through the opening; at least one restricting portion rigidly formed in the connector housing for retaining the terminal fitting to prevent the terminal fitting from coming out backward in a longitudinal direction by being engaged with the terminal fitting; and a cover portion to be so mounted on the connector housing as to open and close the opening in the side surface of the connector housing, wherein at least one restricting wall for preventing a leading end portion of the terminal fitting from being lifted up by pressing an upper part of the leading end portion of the terminal fitting is formed to project inwardly from the inner surface of a front wall, wherein the restricting portion locks a rear end of a tube portion of the terminal fitting such that the terminal fitting can be temporarily set by slipping the leading end portion of the terminal fitting under the restricting wall and locking the rear end thereof by the restricting portion, characterized in that one or more guide portions (18; 19) for guiding a sliding movement of the cover portion at the time of opening and/or closing the opening from a rear side toward the front side in the longitudinal direction of the terminal fitting are formed on wall surfaces of the opening substantially facing each other and extending in the longitudinal direction of the terminal fitting, and one or more leading end surfaces of the restricting walls serve as one or more stopper portions which come into contact with the cover portion to define a front end position of the cover portion when the cover portion is closed. a connector housing formed such that an opening is formed in at least one side surface to expose the cavity over the substantially entire length and the terminal fitting can be at least partly accommodated into the cavity through the opening; at least one restricting portion rigidly formed in the connector housing for retaining the terminal fitting to prevent the terminal fitting from coming out backward in a longitudinal direction by being engaged with the terminal fitting; and a cover portion to be so mounted on the connector housing as to open and close the opening in the side surface of the connector housing, wherein at least one restricting wall for preventing a leading end portion of the terminal fitting from being lifted up by pressing an upper part of the leading end portion of the terminal fitting is formed to project inwardly from the inner surface of a front wall, wherein the restricting portion locks a rear end of a tube portion of the terminal fitting such that the terminal fitting can be temporarily set by slipping the leading end portion of the terminal fitting under the restricting wall and locking the rear end thereof by the restricting portion, characterized in that one or more guide portions (18; 19) for guiding a sliding movement of the cover portion at the time of opening and/or closing the opening from a rear side toward the front side in the longitudinal direction of the terminal fitting are formed on wall surfaces of the opening substantially facing each other and extending in the longitudinal direction of the terminal fitting, and one or more leading end surfaces of the restricting walls serve as one or more stopper portions which come into contact with the cover portion to define a front end position of the cover portion when the cover portion is closed.