To extract an undisturbed sample by dry drilling, and easily perform pressing-in and withdrawing of a sampler even if collecting depth of the sample is deep.

After drilling up to fixed depth by a hollow auger 1 with an openable/closeable bit 3 mounted on the extremity, a sampling rod 34 with a sampler mounted on the extreme end is inserted into the hollow auger 1. By opening the bit 3 and pressing the sampler 35 in the drilled hole bottom, a sample is collected into the sampler 35, and the sampler 35 is pulled up.