Impact fastening tool

An impact fastening tool comprising:

• a motor for generating a driving force;
• an output shaft for fastening an object to be fastened;
• a strike mechanism including a hammer and an anvil integrally rotated with the output shaft, generating impact force by striking the anvil by the hammer and transmitting the driving force generated by the motor to the output shaft with the impact force;
• a strike detector for detecting occurrence of strikes of the anvil by the hammer;
• a current detector for detecting current information in an interval of the strikes;
• a strike judger for judging whether detection of the strike by the strike detector is real or unreal with using current information;
• a fastening torque calculator for calculating a fastening torque equivalent to a fastening torque generated by the impact forces with ignoring the strike judged unreal by the strike judger;
• and
• a motor controller for stopping driving of the motor at a time when the calculated fastening torque reaches to a predetermined reference value.