Surveying device

A surveying device 3 configured to perform a survey by tracking, as a survey target, a prism 13 attached to a camera 11 of a movable imaging device 2, includes an electronic distance 5 meter 33 configured to measure a distance to the survey target; a horizontal angle detector 41 and a vertical angle detector 42 each configured to measure an angle; a main body 3a supporting these members; a time obtainer 47 configured to obtain a GPS time from a GPS satellite; a tilt sensor 48 configured to detect a posture of the main body 3a; a calibrator 49 configured to calibrate the tilt sensor 48; and a survey controller 40 that causes the calibrator 49 to perform 10 calibration during a period in which the time obtainer 47 obtains the GPS time, as an advance preparation to be performed before the measurement.