Abstract: An apparatus and a method for controlling the operation of a reach tower crane, in which a horizontal boom can safely and securely be operated or stored by one operator in the cab, and in which even if sensors are out of order, the stability of the crane can be secured. The system has a plurality of sensors for detecting a condition of an actuator (6) actuating an apparatus to operate or store a horizontal boom (5), a controller (36) for sending a control signal based on signals from the sensors, and hydraulic apparatuses for controlling various actuators in accordance with the control signal. Further, an operation lever and an operation switch are used to extend or store the horizontal boom (5).