An apparatus includes a rotation section to engage with a disk in a housing and rotate the disk around an axis of the disk; an information reading/recording section to carry out reading and/or recording from/to the disk; a holding member to hold the rotation section and/or the information reading/recording section; and a moving section to move the holding member in a direction that the holding member moves toward the disk and/or that the holding member moves away from the disk. The moving section includes a first cam member surrounding at least part of the holding member for arcuate movement along the holding member around an axis. The holding member and/or the first cam member has a grooved portion inclined with respect to a direction along the axis of the arcuate movement while the other has a first engaging portion for engaging with the grooved portion.