This measurement system of a working machine is provided with: an image acquisition unit which acquires, by an image capturing device mounted on a revolving body of the working machine, an image of a construction target photographed while the revolving body is revolving; a three-dimensional position calculation unit which calculates the three-dimensional position of the construction target on the basis of the image; a revolving data acquisition unit which acquires revolving data on the revolving body; a determination unit which determines whether the revolving data satisfies a prescribed revolving condition; and an output unit which outputs a revolving instruction signal on the basis of the determination result of the determination unit.