A waterproof connector comprising: a housing for housing terminals connected to electric wires; a waterproof member provided between the housing and the electric wires; and a rear holder attached to the housing and configured to prevent the waterproof member from coming off the housing, wherein the rear holder comprises a first mating member and a second mating member which are formed in an identical shape, the first mating member and the second mating member being coupled with each other with a first contact surface of the first mating member and a second contact surface of the second mating member being in contact with each other and with the electric wires being interposed in between the first mating member and the second mating member, wherein the first mating member and the second mating member form wire housing portions for housing the corresponding electric wires with the first contact surface and the second contact surface being in contact with each other, wherein the first mating member comprises a first engaging portion having a first engaging recess and a first engaging projection, wherein the second mating member comprises a second engaging portion having a second engaging recess and a second engaging projection, wherein the first engaging portion and the second engaging portion are configured to symmetrically engage with each other and keep a coupled state of the first mating member and the second mating member with the first contact surface and the second contact surface being in contact with each other, characterized in that the first engaging projection is insertable in the second engaging recess in an extending direction of the electric wires and engageable with the second engaging recess, the second engaging projection is insertable in the first engaging recess in the extending direction of the electric wires and engageable with the first engaging recess, the first engaging recess and the first engaging projection are provided in a middle of the first contact surface between the wire housing portions, and the second engaging recess and the second engaging projection are provided in a middle of the second contact surface between the wire housing portions, wherein the first engaging recess is a groove formed into an L-shape, the second engaging recess is a groove formed into an L-shape, the first engaging projection projects from the first contact surface and is formed into an inverse L-shape of the second engaging recess, and the second engaging projection projects from the second contact surface and is formed into an inverse L-shape of the first engaging recess. a housing for housing terminals connected to electric wires; a waterproof member provided between the housing and the electric wires; and a rear holder attached to the housing and configured to prevent the waterproof member from coming off the housing, wherein the rear holder comprises a first mating member and a second mating member which are formed in an identical shape, the first mating member and the second mating member being coupled with each other with a first contact surface of the first mating member and a second contact surface of the second mating member being in contact with each other and with the electric wires being interposed in between the first mating member and the second mating member, wherein the first mating member and the second mating member form wire housing portions for housing the corresponding electric wires with the first contact surface and the second contact surface being in contact with each other, wherein the first mating member comprises a first engaging portion having a first engaging recess and a first engaging projection, wherein the second mating member comprises a second engaging portion having a second engaging recess and a second engaging projection, wherein the first engaging portion and the second engaging portion are configured to symmetrically engage with each other and keep a coupled state of the first mating member and the second mating member with the first contact surface and the second contact surface being in contact with each other, characterized in that the first engaging projection is insertable in the second engaging recess in an extending direction of the electric wires and engageable with the second engaging recess, the second engaging projection is insertable in the first engaging recess in the extending direction of the electric wires and engageable with the first engaging recess, the first engaging recess and the first engaging projection are provided in a middle of the first contact surface between the wire housing portions, and the second engaging recess and the second engaging projection are provided in a middle of the second contact surface between the wire housing portions, wherein the first engaging recess is a groove formed into an L-shape, the second engaging recess is a groove formed into an L-shape, the first engaging projection projects from the first contact surface and is formed into an inverse L-shape of the second engaging recess, and the second engaging projection projects from the second contact surface and is formed into an inverse L-shape of the first engaging recess.