Surveying instrument

A surveying instrument comprising a monopod installed on a reference point, a surveying instrument main body which is provided at a known distance from a lower end of said monopod and at a known angle with respect to an axis of said monopod and has a reference optical axis and an operation panel which is provided on said monopod and has a display module, wherein said surveying instrument main body includes a distance measuring unit configured to irradiate a distance measuring light, to receive a reflected distance measuring light and to measure a distance to an object to be measured, an optical axis deflector configured to deflect said distance measuring light with respect to said reference optical axis, a measuring direction image pickup module which includes said object to be measured and is configured to acquire an observation image in a predetermined relationship with said reference optical axis and an arithmetic control module configured to make said distance measuring unit perform a distance measurement along a predetermined scan pattern, and wherein said arithmetic control module is configured to continuously cut out sighting images around a tracking point set in said observation image, to set a first cutout sighting image as a reference sighting image, to calculate a movement amount of a subsequent sighting image with respect to said reference sighting image by an image matching of said reference sighting image and said subsequent sighting image and to control said optical axis deflector based on a calculation result in such a manner that said tracking point is positioned at a center of said subsequent sighting image.