An electric tool comprising: a motor ; an attachment unit configured to receive a tip tool attached thereto; a transmission mechanism configured to transmit motive power of the motor to the attachment unit ; a drive control unit configured to control the motor ; a number of revolutions detection unit configured to detect a number of revolutions (r1) of a first detection target shaft, wherein the first detection target shaft is arranged between the motor and the tip tool or is a rotary shaft of the motor or an output shaft or a shaft of a tip tool, wherein the number of revolutions unit is configured to detect at least one of a rotational velocity, an angular velocity, or an angular acceleration and a torque detection unit configured to detect a load torque (Tq1) of a second detection target shaft, wherein the second detection target shaft is arranged between the motor and the tip tool or is the rotary shaft of the motor or the output shaft or the shaft of the tip tool, the first detection target shaft and the second detection target shaft being the same shaft or two different shafts, and the drive control unit being configured to detect, based on the number of revolutions (r1) detected by the number of revolutions detection unit and the load torque (Tq1) detected by the torque detection unit , an unstable behavior of at least one of the tip tool, the first detection target shaft, or the second detection target shaft and to either decelerate, or stop running, the motor when detecting the unstable behavior, characterized in that the drive control unit is configured to detect the unstable behavior based on a degree of increase (D1) in the load torque (Tq1) and a degree of decrease (D2) in the number of revolutions (r1). a motor ; an attachment unit configured to receive a tip tool attached thereto; a transmission mechanism configured to transmit motive power of the motor to the attachment unit ; a drive control unit configured to control the motor ; a number of revolutions detection unit configured to detect a number of revolutions (r1) of a first detection target shaft, wherein the first detection target shaft is arranged between the motor and the tip tool or is a rotary shaft of the motor or an output shaft or a shaft of a tip tool, wherein the number of revolutions unit is configured to detect at least one of a rotational velocity, an angular velocity, or an angular acceleration and a torque detection unit configured to detect a load torque (Tq1) of a second detection target shaft, wherein the second detection target shaft is arranged between the motor and the tip tool or is the rotary shaft of the motor or the output shaft or the shaft of the tip tool, the first detection target shaft and the second detection target shaft being the same shaft or two different shafts, and the drive control unit being configured to detect, based on the number of revolutions (r1) detected by the number of revolutions detection unit and the load torque (Tq1) detected by the torque detection unit , an unstable behavior of at least one of the tip tool, the first detection target shaft, or the second detection target shaft and to either decelerate, or stop running, the motor when detecting the unstable behavior, characterized in that the drive control unit is configured to detect the unstable behavior based on a degree of increase (D1) in the load torque (Tq1) and a degree of decrease (D2) in the number of revolutions (r1). <EOS>