A portable small mine detecting device for detecting a mine by transmitting a radio wave and detecting the NQR of nitrogen 14 atoms contained in the mine by means of a high-sensitivity, high-temperature superconducting SQUID magnetic sensor. Each timer is enqueued in one slot in one of multiple timing wheels. Further, a damper unit is disposed between the outlet port of the pump and the orifice to reduce pressure pulsation caused by operation of the piston, thereby improving product reliability through noise reduction during brake control. Each side wall has a recess in proximity to the front wallupper wall interface.