A forward/ reverse control system for a work machine cancels a second control state, in which forward/reverse switching control is performed by a second forward/reverse control means, by an operation of a first forward/reverse control means to return to a first control state in which forward/reverse switching control is performed by the first forward/reverse control means. The system is provided with a F-N-R lever unit 30 (the first forward/reverse control means) and F-N-R switch unit 40 (the second forward/reverse control means) that instruct forward, reverse or neutral, a controller 42 which performs forward/reverse switching control by giving priority to an instruction from the F-N-R lever unit 30 over an instruction from the F-N-R switch unit 40, and a selector switch 41 which by an operation of a switching control member 41a, instructs the controller 42 to switch to the second control state or to cancel the second control state. As a consequence, the system has made it possible to return to the first control state without an operation of the first forward/reverse control means.