To provide a boring machine capable of eliminating the need for installation of a temporary scaffold, holding the good conditions of natural environment and scenery, and performing boring safely and easily when a sloped ground where obstacles such as trees are located is bored.

A boring machine comprises a fixed device fixed by inserting an expandable balloon 14 into a fixing hole provided in the ground and inflating it with a fluid pressure, a slide arm 10 which is installed swingably on the fixed device 12 and extended movably in the direction perpendicular to a digging direction, a guide frame 8 which is installed on the slide arm 10 and extends in the direction reverse to the digging direction, and a hydraulic cylinder 24 which is installed on the guide frame 8 and supports a digging device 1 movably in the digging direction.