Tilting angle control devices wherein each tilting angle control device (1; 1A; 1B) is configured to control a tilting angle (α) of a variable displacement pump (10L, 10R) configured to discharge a pressure liquid, the amount of which corresponds to the tilting angle, the tilting angle control device comprising: an operation unit (19, 20) configured to output a pressure command signal corresponding to an operation amount of the operation unit, in order to drive an actuator (3 to 9); a control unit (60; 60A) configured to output a pressure control signal corresponding to the pressure command signal; a proportional control valve configured to output pilot pressure corresponding to the pressure control signal; a tilt adjustment mechanism configured to adjust the tilting angle of the variable displacement pump such that the tilting angle becomes an angle corresponding to the pilot pressure; and a pressure detector configured to detect the pilot pressure and to output to the control unit a pressure feedback signal corresponding to the detected pilot pressure, wherein: the control unit calculates the pressure control signal based on the pressure feedback signal and the pressure command signal; and the proportional control valve has a valve characteristic of outputting predetermined pilot pressure corresponding to the pressure control signal input to the proportional control valve; characterised in that the valve characteristic of the proportional control valve and valve characteristics of other proportional control valves of other tilting angle control devices, which are of the same type as the proportional control valve, are different from one another, and in that the control unit stores the valve characteristic and calculates the pressure control signal based on the pressure feedback signal, the pressure command signal, and the valve characteristic. an operation unit (19, 20) configured to output a pressure command signal corresponding to an operation amount of the operation unit, in order to drive an actuator (3 to 9); a control unit (60; 60A) configured to output a pressure control signal corresponding to the pressure command signal; a proportional control valve configured to output pilot pressure corresponding to the pressure control signal; a tilt adjustment mechanism configured to adjust the tilting angle of the variable displacement pump such that the tilting angle becomes an angle corresponding to the pilot pressure; and a pressure detector configured to detect the pilot pressure and to output to the control unit a pressure feedback signal corresponding to the detected pilot pressure, wherein: the control unit calculates the pressure control signal based on the pressure feedback signal and the pressure command signal; and the proportional control valve has a valve characteristic of outputting predetermined pilot pressure corresponding to the pressure control signal input to the proportional control valve; characterised in that the valve characteristic of the proportional control valve and valve characteristics of other proportional control valves of other tilting angle control devices, which are of the same type as the proportional control valve, are different from one another, and in that the control unit stores the valve characteristic and calculates the pressure control signal based on the pressure feedback signal, the pressure command signal, and the valve characteristic. the control unit calculates the pressure control signal based on the pressure feedback signal and the pressure command signal; and the proportional control valve has a valve characteristic of outputting predetermined pilot pressure corresponding to the pressure control signal input to the proportional control valve; characterised in that the valve characteristic of the proportional control valve and valve characteristics of other proportional control valves of other tilting angle control devices, which are of the same type as the proportional control valve, are different from one another, and in that the control unit stores the valve characteristic and calculates the pressure control signal based on the pressure feedback signal, the pressure command signal, and the valve characteristic.