A free-space optical communication apparatus for transmitting and receiving light waves to and from an artificial satellite orbiting an earth orbit, the free-space optical communication apparatus comprising: a transmission light wave generating unit configured to generate an uplink transmission light wave (Tx) to be transmitted to the artificial satellite through an uplink propagation path; a telescope having an aperture for collecting downlink light emitted from the artificial satellite , characterized in that the telescope is realized such that the downlink light emitted from the artificial satellite and collected through the aperture includes (i) a downlink reception light wave (Rx) that propagates through a downlink propagation path and (ii) a path propagation light that propagates through a space including at least a part of the uplink propagation path through which the uplink transmission light wave generated by the transmission light wave generating unit is to be transmitted to the artificial satellite , wherein said at least a part of the uplink propagation path does not overlap with the downlink propagation path through which the downlink reception light wave propagates; in that a wavefront sensor configured to detect wavefront distortions of the downlink reception light wave and the path propagation light collected by the telescope is provided; in that a control unit configured to generate a control signal based on the wavefront distortion of the path propagation light detected by the wavefront sensor is provided; and in that a deformable mirror is provided, configured to correct the propagation path based on the control signal generated by the control unit to guide the uplink transmission light wave (Tx) to the artificial satellite through the telescope and via the corrected uplink propagation path. a transmission light wave generating unit configured to generate an uplink transmission light wave (Tx) to be transmitted to the artificial satellite through an uplink propagation path; a telescope having an aperture for collecting downlink light emitted from the artificial satellite , characterized in that the telescope is realized such that the downlink light emitted from the artificial satellite and collected through the aperture includes (i) a downlink reception light wave (Rx) that propagates through a downlink propagation path and (ii) a path propagation light that propagates through a space including at least a part of the uplink propagation path through which the uplink transmission light wave generated by the transmission light wave generating unit is to be transmitted to the artificial satellite , wherein said at least a part of the uplink propagation path does not overlap with the downlink propagation path through which the downlink reception light wave propagates; in that a wavefront sensor configured to detect wavefront distortions of the downlink reception light wave and the path propagation light collected by the telescope is provided; in that a control unit configured to generate a control signal based on the wavefront distortion of the path propagation light detected by the wavefront sensor is provided; and in that a deformable mirror is provided, configured to correct the propagation path based on the control signal generated by the control unit to guide the uplink transmission light wave (Tx) to the artificial satellite through the telescope and via the corrected uplink propagation path. <EOS>