WORKING DETECTION DEVICE

PROBLEM TO BE SOLVED: To provide a working detection device capable of reliably working a workpiece and shortening a cycle time of the working.SOLUTION: A control device advances a rotary main shaft by a feed mechanism while rotating the rotary main shaft, as an advancing operation (S5). The control device then detects a working start P1 (S8) when a value of a load voltage V measured by a measurement device is continuously higher than a predetermined working initial voltage value V1 during a predetermined working initial time t1 (S6, S7) as an initial detection operation. Then, the control device detects a working completion P2 (S11) when the value of the load voltage V measured by the measurement device is continuously lower than a predetermined working terminal voltage value V2 during a predetermined working terminal time t2 (S9, S10) as a terminal detection operation after the detection of the working start P1. Thereafter, the control device retreats the rotary main shaft by the feed mechanism (S13) as a retreat operation when the working completion P2 is detected.