A seek control device controls the seek of a plant to prevent the position shift due to an error between a model for generating seek current and a model of the plant. When the seek trajectory is provided by seek trajectory generation for controlling the seek of a plant, the frequency characteristic of a feed back loop is changed according to the seek time and the gain of the position shift component due to the shift of the actual plant and the model of the plant is increased, so as to suppress the position shift by the feed back loop. Dispersion of the seek time can be decreased, and an overrun or underrun can be prevented.