To easily and correctly judge the timing to exchange a drill by anybody without any supervision of a skilled worker during the work.

This device is provided with a torque load detection part 11; a thrust load detection part 12; a maximum torque value detection part 13; a maximum thrust value detection part 15; a torque value memory part 9; and a thrust value memory part 10 which successively detect the maximum torque value Tfmax and the maximum thrust value Sfmax for a plurality of drill holes 65. An upper limit torque value input key 26a and an upper limit thrust value input key 26b which are capable of freely inputting an arbitrary upper limit torque value TFx and an arbitrary upper limit thrust value SFx; an upper limit torque value memory part 6 and an upper limit thrust value memory part 7 are provided to indicate and output the upper limit torque value TFx and the upper limit thrust value SFx, to temporally indicate and output the maximum torque value Tfmax and the maximum thrust value Sfmax, and to output each alarm value and comparative judgment signal.