A deformable mirror includes a deformable section on which a reflecting surface and a COM electrode are formed, a fixing section which fixes the deformable section, a driving and sensing electrode (driving force generating unit) which has a plurality of driving and sensing electrodes provided facing the COM electrode, and which drives the deformable section by applying an electric potential difference between the COM electrode and the driving and sensing electrode, and a capacitance detecting circuit which detects simultaneously a plurality of capacitances between the COM electrode and the driving and sensing electrode.
