To provide a technology capable of correctly obtaining a position and an excavating direction of an excavator, even in a curved shaft.

A method of measuring the position of an excavator includes the steps of placing downward, at least three mirrors whose positions have been identified, collimating the mirrors by laser-beam distance measuring means respectively installed on at least three identified points on a surface to be measured specified by the excavator and measuring distances from the respective identified points to the respective mirrors; measuring the tilt angle of the excavator, based on position information of each mirror and the distance information from each identified point to each mirror; and calculating the position and the excavating direction of the excavator, based on the distance from each identified point to respective mirror and the tilt angle of the excavator.