Attachment device and total station

An attachment device (46) for attaching and removing a distance measuring instrument (3) to and from an angle measuring instrument comprises a base unit (61) to which the distance measuring instrument is fixed, a fixing unit (55) for fixing the base unit to the angle measuring instrument, and an optical member (52) for deflecting a distance measuring light from the distance measuring instrument so as to concur with a sighting optical axis of the angle measuring instrument.