To enable a plurality of kinds of rods having different cross-sectional shapes to be used by one boring machine.

A boring machine comprises: a rotating table 1 installed in a rotary section which drives a rod rotationally and rotating by power; a first adapter 10; and a second adapter, the first and second adapters being detachably and alternatively attached to the rotating table 1 and rotating along with the rotating table 1. The first adapter 10 has a structure corresponding to the cross-sectional shape of a first rod RD1 to support the first rod RD1 and making the first rod RD1 rotate along with rotation of the first adapter 10, and the second adapter has a structure corresponding to the cross-sectional shape of a second rod to support the second rod and making the second rod rotate along with rotation of the second adapter. The first adapter 10 and the second adapter are formed so that the rotary shaft of the rotating table 1 coincides with the rotary shaft of the first rod RD1 and also with that of the second rod.