The invention provides a measuring instrument, which comprises a measuring unit for projecting a distance measuring light toward an object to be measured and for performing a distance measurement by receiving a reflected light from the object to be measured, and an attitude detecting device integrally provided with the measuring unit, wherein the attitude detecting device has tilt sensors for detecting a horizontality and relative tilt angle detectors for tilting the tilt sensors and for detecting a tilt angle of the measuring unit with respect to the horizontality under such condition that the tilt sensors detects the horizontality so that the horizontality is detected by the tilt sensor, and wherein the distance measurement of the object to be measured is performed by the measuring unit, and a vertical angle of a measuring point is determined based on the result of the tilt detection by the attitude detecting device.