A disclosed disk clamping mechanism includes a turntable fixed on a rotational shaft of a spindle motor to rotate a flexible thin optical disk, a stabilizer member configured to suppress a run-out of the flexible thin optical disk by an applying aerodynamic force to the rotating flexible thin optical disk so as to stabilize the run-out of the rotating flexible thin optical disk, and a clamper movably supported in a center of the stabilizer member in a direction perpendicular to a surface of the flexible thin optical disk. In the disclosed disk clamping mechanism, the flexible thin optical disk is sandwiched between the turntable and the clamper such that the turntable and the clamper rotate the flexible thin optical member sandwiched in-between.