A tool is equipped with a torque sensor, suited for a tightening task of a fastening component of a device such as a fluid control system that requires a large number of fastening components for assembly and has a narrow space for access to the fastening components, and capable of automatically detecting a tightening torque. The tool includes a torque sensor capable of detecting a tightening torque for tightening a fastening component acting on a bit. The torque sensor initiates measurement of the tightening torque when the tightening torque detected exceeds a set threshold value, completes measurement when the tightening torque detected falls below the set threshold value and a set time elapses, and outputs torque-related data formed on the basis of measurement data from measurement initiation to measurement completion and including a measurement time. The torque-related data includes a peak value of the measurement data.