a deformable mirror which compensates a wavefront aberration of a light flux entered, the deformable mirror including a plurality of electrodes, and a thin-film mirror which changes a configuration thereof in accordance with a voltage value applied to each of the electrodes;

an optical system provided with the deformable mirror, and including an object subjected to aberration compensation;

a wavefront sensor which receives the light flux traveled through the object and the deformable mirror, and which measures the wavefront aberration of the light flux; and

a controller configured to:

calculate a first voltage value applied to each of the electrodes, on the basis of differences from a signal outputted from the wavefront sensor between application points on the thin-film mirror and target points both corresponding to the electrodes respectively;

determine a superposition amplitude value of each expansion mode according to a polynomial of wavefront aberration, wherein a voltage template as a voltage alignment data for the electrodes which induces the corresponding expansion mode is previously stored for each of the expansion modes according to the polynomials of the wavefront aberrations, and calculate a second voltage value applied to each of the electrodes by using the voltage templates previously stored, such that the wavefront aberration obtained by the wavefront sensor becomes a desired aberration;

determine the voltage value applied to each of the electrodes, by mainly using the calculated second voltage value in an initial stage of compensation of the configuration of the thin-film mirror of the deformable mirror and by mainly using the calculated first voltage value in an end stage of the compensation of the configuration of the thin-film mirror; and

repeat the compensation of the configuration of the thin-film mirror on the basis of the determined voltage value, such that the wavefront aberration of the light flux measured by the wavefront sensor is suppressed.