To obtain a high responsiveness over a whole operation region of an operation lever without causing erroneous operation in an actuator drive controller.

In a controller 20, a lever angle θ1, a lever speed ω, and a lever acceleration dω/dt of an operation lever 10a are calculated from pulse signals of a potentiometer 11, and a command current value (i) corresponding to the lever angle θ1 is calculated. Moreover, a distance (angle) L at which the operation lever 10a moves in Δt seconds is estimated based on the lever speed and the acceleration. When this distance L exceeds a threshold value determined in advance, the controller 20 judges that an overcurrent should be applied, calculates an overcurrent value (magnitude, direction, and time of overcurrent) based on a current value for generating a pilot pressure equivalent to a lever position after Δt seconds (current position + the estimated travel distance), adds the value to the command current value (i), and outputs the obtained value to an electromagnetic proportional control valve 30a or 30b.