A technique that enables easily determining an attitude of a laser scanning apparatus is provided. A surveying device includes a sunlight incident direction measurement unit, a Sun direction acquisition unit, and an attitude calculator. The sunlight incident direction measurement unit measures an incident direction of sunlight that enters a laser scanning apparatus, based on a detected waveform of incident light entering the laser scanning apparatus. The Sun direction acquisition unit acquires a direction of the Sun as seen from the laser scanning apparatus, from astronomical data, based on a position of the laser scanning apparatus. The attitude calculator calculates an attitude of the laser scanning apparatus in an absolute coordinate system, based on the incident direction of sunlight and the direction of the Sun as seen from the laser scanning apparatus, which is acquired from the astronomical data.