A disk apparatus includes: an actuator 7 ; a driver 10 ; a voltage detector 11 for outputting first voltage signal Ed which is produced in a driving coil 5 of the actuator 7 ; a voltage signal adjuster 16 for outputting pseudo disturbance signal ur and generating second voltage signal Ed + from pseudo disturbance signal ur , driving signal u , first voltage signal Ed , and disturbance estimation signal τd est ; a disturbance estimator 12 for estimating the magnitude of disturbance load τ d applied to a magnetic head 2 from driving signal u and second voltage signal Ed + to output disturbance estimation signal τd est ; a position detector 13 for generating position error signal e which corresponds to a current position of the magnetic head 2 ; a position controller 14 for generating control signal c from position error signal e ; and a corrector 15 for generating driving signal u from disturbance estimation signal τd est and position control signal c .