PURPOSE: To cut safely and at low cost a concrete structure in an elevated place with a wire saw.

CONSTITUTION: An arm 7 in a U-shaped external side face is fixed at its side wall on one side through a revolving ram 6 to the front end of a boom 5 that is extendable and adjustable in angles. The arm 7 is constructed in U-shaped cross section and guide pulleys 11 are provided to a cavity formed by the aforementioned U shape, and a wire saw 12 is stretched around the pulleys 11. Then cutting is made with the wire saw 12 that is driven and is pressed down to a structure to be cut, and the revolving ram 6 is turned, according to the angle of cutting required for cutting the structure to be cut. Thereby a concrete structure can be cut safely and at low cost.