To provide an actuator driving device for driving a plurality of hydraulic operation parts by using one variable speed motor and one hydraulic tank, which increases the energy efficiency and secures the sufficient operation force.

The actuator driving device comprises: the variable speed motor 1 for controlling the rotational frequency; a variable speed control device 2 for controlling the rotational frequency of the variable speed motor; a hydraulic pump 3 driven by the variable speed motor; a hydraulic control valve 5 for controlling the feed of a pressure oil fed to each hydraulic operating part 4; and a control device 6 for controlling the motion of the plurality of hydraulic pressure control valves 5. The gross flow rate of the hydraulic oil fed to the hydraulic operating parts 4 is calculated and the rotational frequency of the variable speed motor 1 is controlled according to the gross flow rate.