A battery charge/discharge control device which performs battery charge/discharge control in a working machine with a battery capable of storing electric energy generated by a generator motor coupled to an engine and driving the generator motor or at least one of other electric actuators by the stored electric energy and a controller which controls a distribution of the electric energy among the battery, the generator motor, and the electric actuator, wherein the controller performs the charge/discharge control in which the electric energy of the battery is discharged when the engine is driven and recharging to the battery is permitted on a condition that a state in which an engine speed is equal to or lower than a predetermined engine speed is maintained for a predetermined time after the battery is completely discharged.