working device the boom cylinder 13 the arm cylinder 14 or the attachment cylinder 15 so as to rotate the working device the boom 10 the arm 11 or the bucket 12 and the supply of the pressure oil from the hydraulic pump 21 to the working device is stopped so as to stop the rotation of the working device the hydraulic circuit 20 performs the supply of the pressure oil from the hydraulic pump 21 to the working device or the stop of the supply of the pressure oil from the hydraulic pump 21 to the working device by the switching valve 22 on off operation of the switching valve 22 the hydraulic pump 21 of the hydraulic circuit 20 is configured so as to be driven with the engine 9 as the power source the pressure oil thermometer 23 of the hydraulic circuit 20 is configured so as to measure temperature of the pressure oil of the hydraulic circuit 20 the control device 30 of the backhoe 1 has an ecu a hydraulic circuit control unit not shown and the like and is connected to the traveling device 2 the revolving device 3 the revolving base 6 the operation part 8 and the engine 9 of the revolving device 3 the working device 4 the sensor 11 b of the working device 4 the hydraulic circuit 20 the hydraulic pump 21 the switching valve 22 and the pressure oil thermometer 23 of the hydraulic circuit 20 and the like the control device 30 is configured so as to control the traveling device 2 the revolving device 3 the revolving base 6 the operation part 8 and.