To obtain a topography measuring apparatus which is installed at a moving body or the like, by which a topography can be grasped in real time on the basis of an own position measured by using a global positioning system(GPS) signal, on the basis of a three-dimensional posture and on the basis of a movement distance measured by using a movement range finder and by which a topography in a wide range and a topography changed due to a construction operation at an engineering works site or the like can be grasped at any time.

This topography measuring apparatus is constituted of a GPS antenna array 1 which is constituted of a plurality of GPS antennas. The measuring appratus is constituted of a GPS measuring device 2 by which a three- dimensional posture, i.e., an absolute direction, a pitch angle, a roll angle and an own position can be obtained on the basis of a received GPS signal. The measuring apparatus is constituted of a calculation and control device 3 which controls a device and which calculates a numerical value. The measuring apparatus is constituted of a recording device 5 which records obtained data. The measuring apparatus is constituted of a movement range finder 4. The topography is measured in real time on the basis of the measured own position, the measured three-dimensional posture and a movement distance.