Feedback control of an object which moves back and forth in a straight line along a linear guide is performed through PID control. A parameter adjustment unit which determines the control parameters to be used for PID control performs feedback control and determines the optimal value of control parameters by means of an evaluation function based on the error between the measured value of the current velocity and the target velocity, for the control parameters of maximum reverse voltage and at least one from among proportional coefficient (CP), differential coefficient CD), integral coefficient CI), and frictional coefficient (CF).