To provide a working apparatus for well drilling works, safely and quickly performing well drilling works without constructing a drilling derrick.

In this working apparatus for well drilling works, two side frames are disposed parallel, both ends of each side frame are provided with legs, a central frame is fixed between the two side frames, an arm base and a boring machine base are set on the central frame, the arm base is provided with an arm and a hydraulic operating means for operating the arm with oil pressure to adjust the length and inclination angle of the arm, and the boring machine base is provided with a boring machine and a wire hoisting means. A hoisting wire is mounted on a hoisting drum of the wire hoisting means to be hoisted, and guided by the tip of the arm, and holds a lifting block in the vicinity of the boring machine to adjust the height level thereof.