A servomotor control device includes a servomotor, driven body, connection mechanism, first position detection section, second position detection section, and motor control unit. The motor control unit has: a dual position control section that performs semi-closed FB control based on a high-frequency component of a first deviation between a position command value and the position of the servomotor detected by the first position detection section, and full-closed FB control based on a low-frequency component of a second deviation between the position command value and the position of the driven body detected by the second position detection section; an acquisition section that acquires a magnitude of rigidity of the connection mechanism; and a varying section that varies a proportion of the semi-closed FB control to full-closed FB control in the dual position control section, in response to the acquired magnitude of rigidity of the connection mechanism.