A surveying apparatus comprises an observation optical system 1 having an image sensor 8 for outputting a digital image signal and a zoom optical system 7, a reference-pattern projection optical system 18 for making a reference pattern 14 enter the observation optical system in an infinity state and for forming an image on the image sensor, a rotation mechanism 5 capable of rotating the observation optical system and the reference-pattern projection optical system integrally in two directions of horizontal and vertical, a horizontal angle detector 15 and a vertical angle detector 16 for detecting a horizontal angle and a vertical angle of rotation in the two directions of the rotation mechanism, and an arithmetic control unit 9, and in the surveying apparatus, the arithmetic control unit measures the horizontal angle and the vertical angle of a sighting point based on detection results of the horizontal angle detector and the vertical angle detector and based on a difference between the reference pattern on the image sensor and the sighting point of the observation optical system.