An aligning device for a disk recording medium capable of reducing eccentricity using a simple structure, without an increase in cost, is provided. An aligning member has a tapered portion that contacts with a center hole of a disk, and fits with a guide portion that is fixed to a turntable with a sliding gap therebetween. The sliding gap between the aligning member and the guide portion is formed such that a leading end side sliding gap of the turntable in the sliding direction of the aligning member differs from a trailing end side sliding gap of the disk side in the sliding direction. The leading end side sliding gap is formed smaller than the trailing end side sliding gap. The amount of eccentricity of the disk becomes smaller according to this structure.