According to an aspect of an embodiment, a memory device has a medium including a plurality of tracks, each of which has a plurality of sectors separated by a plurality of servo areas, for storing data in the sectors of the tracks, a head for writing data into and reading data from the medium and a controller for determining whether the head has read out data from a sector on a target track correctly or not in reference to information obtained from servo areas sandwiching the sector and for driving the head so as to retry reading out data from the sector when the controller determines that the head failed to have read out data on the target track.