A connector for preventing unlocking, comprising: a signal pin transferring a signal; a body into which the signal pin is inserted and which is electrically isolated from the signal pin by an insulator and transfers a ground voltage; a first housing having a hollow portion defined therein, into which one end of the body is inserted, a thread groove for screw-coupling, which is defined in an inner circumferential surface of one end thereof, and at least one protruding portion or a plurality of fixing grooves formed on or in an inner circumferential surface of the other end thereof; and a second housing having a hollow portion defined therein, into which the other end of the body is inserted and through which the second housing is moved along an outer circumferential surface of the body in an axial direction, and one of the at least one protruding portion and the plurality of fixing grooves, which is not formed at the first housing but is formed on or in an outer circumferential surface of one end thereof, wherein, when the one end of the second housing is inserted and fixed between the inner circumferential surface of the other end of the first housing and the outer circumferential surface of the body, the at least one protruding portion is coupled in the plurality of fixing grooves so as to prevent rotation of the first housing with reference to the second housing; characterized in that when the thread groove of the first housing is screw-coupled; the second housing is fixed in a state in which the fixing grooves and the at least one protruding portion are separated from each other and thus prevented from being moved in an axial direction; and when the at least one protruding portion is coupled in the fixing grooves, the second housing is fixed and prevented from being rotated with reference to the first housing, the second housing being also prevented from being moved in the axial direction by an elastic body, and such elastic body is supported by the body and provides elasticity to the second housing, pushing the second housing in the axial direction towards the first housing, wherein the body has at least one protrusion formed on the other end thereof, and the second housing has at least one through-hole defined in the other end thereof, in which the at least one protrusion is coupled to prevent the second housing from being moved in the axial direction and from being rotated, such movement restrictions being made with reference to the body. a signal pin transferring a signal; a body into which the signal pin is inserted and which is electrically isolated from the signal pin by an insulator and transfers a ground voltage; a first housing having a hollow portion defined therein, into which one end of the body is inserted, a thread groove for screw-coupling, which is defined in an inner circumferential surface of one end thereof, and at least one protruding portion or a plurality of fixing grooves formed on or in an inner circumferential surface of the other end thereof; and a second housing having a hollow portion defined therein, into which the other end of the body is inserted and through which the second housing is moved along an outer circumferential surface of the body in an axial direction, and one of the at least one protruding portion and the plurality of fixing grooves, which is not formed at the first housing but is formed on or in an outer circumferential surface of one end thereof, wherein, when the one end of the second housing is inserted and fixed between the inner circumferential surface of the other end of the first housing and the outer circumferential surface of the body, the at least one protruding portion is coupled in the plurality of fixing grooves so as to prevent rotation of the first housing with reference to the second housing; characterized in that when the thread groove of the first housing is screw-coupled; the second housing is fixed in a state in which the fixing grooves and the at least one protruding portion are separated from each other and thus prevented from being moved in an axial direction; and when the at least one protruding portion is coupled in the fixing grooves, the second housing is fixed and prevented from being rotated with reference to the first housing, the second housing being also prevented from being moved in the axial direction by an elastic body, and such elastic body is supported by the body and provides elasticity to the second housing, pushing the second housing in the axial direction towards the first housing, wherein the body has at least one protrusion formed on the other end thereof, and the second housing has at least one through-hole defined in the other end thereof, in which the at least one protrusion is coupled to prevent the second housing from being moved in the axial direction and from being rotated, such movement restrictions being made with reference to the body.