This diploma describes the measurement of the polygon and the determination of the coordinates of the measurement points in the mine tunnel »Antonijev rov« in Idrija for placement of the mine tunnel into the national coordinate system. Polygon measurement was based by the girus method and trigonometric levelling. The coordinate determination was based separated to vertical and horizontal components. Polygon was connected to a pre-established micro-network of three points outside the mine tunnel. By adjustment we have achieved a few millimetres accuracy, which is appropriate according to the purpose of our measurements. In addition to determining the coordinates and displaying the course of the mine tunnel we have also established a geodetic basis for the possibility of measuring with other technologies such as terrestrial laser scanning.