An optical transmission device for providing stable communication with a partner device by reducing errors in optical axis misalignment. The errors are caused by uneven distribution of the light intensity in a received light beam resulting from atmospheric microscopic fluctuations. One embodiment includes a transmission and receiving unit, which employs two photodetectors, one aligned with and the other misaligned with the optical axis of the optical transmission device. Other embodiments employ a movable means for shifting a photodetector or a lens unit relative to the optical axis of the optical transmission device.