To mechanize a hollow clearing operation for a long hollow dry wood with a large crosssectional shape.

This hollow hole clearing device carries the hollow dry wood 7 disposed on two or a plurality of rotating top chains 2 and 2'to the bed of a device main body and fixes the hollow dry wood 7 at a specified position using clamping mechanisms 4 and 4'. In addition, the device is equipped with copying cones 9 and 9' which are installed opposite to each other at both cross sections of the wood 7 and sliding vertically and to the right/left and hollow clearing drills 10 and 10', arranged at a specified interval. The hollow hole center, of the hollow dry wood 7, which is detected by the copying cones 9 and 9' is cut by the drills 10 and 10' instead of by the copying cones 9 and 9' in a hollow clearing operation.