An interlocking chain type forward and backward actuating device is provided that does not increase workload involved in assembling the device, adjusting the rotation phase, and servicing and maintaining the device. The device is capable of smoothly actuating a driven body by advancing and retracting the body, and of preventing any pulsation or the like of the meshing chain. The interlocking chain type forward and backward actuating device includes chain-guide grooves formed so as to equalize an interlocked-state pin-to-pin distance (D1) between a pair of connecting pins that face each other in a chain interlocking imaginary plane (S) and a rigid-state pin-to-pin distance (D2) between a pair of connecting pins.