A fastening tool configured to fasten a workpiece via a fastener, the fastener having a pin and a cylindrical part, the fastening tool comprising: a fastener-abutment part (61A; 61B) configured to abut on the cylindrical part; a pin-gripping (63A; 63B) part disposed to be movable along a driving axis relative to the fastener-abutment part (61A; 61B) and configured to grip a portion of the pin, the driving axis extending in a front-rear direction of the fastening tool; a motor; a driving mechanism configured to be driven by power of the motor to move the pin-gripping part (63A; 63B) rearward along the driving axis relative to the fastener-abutment part (61A; 61B), thereby fastening the workpiece via the fastener; an input-accepting part configured to accept setting information for a control condition of the motor, the setting information being inputted via an operation part (51; 55) configured to be externally operated by a user; and a motor-control part configured to control operation of the driving mechanism by controlling driving of the motor according to the control condition based on the setting information accepted by the input-accepting part, wherein the fastening tool is configured to use, as the fastener, a tear-off type fastener, in which the pin is inserted through the cylindrical part, the pin includes a shaft part having a small-diameter part for breakage, the pin-gripping part has a plurality of gripping claws configured to grip the shaft part, and is coaxially held within the fastener-abutment part so as to be movable in the front-rear direction along the driving axis relative to the fastener-abutment part, the pin-gripping part being configured such that its gripping force of gripping the shaft part changes as the gripping claws move radially relative to the driving axis along with a movement of the pin-gripping part in the front-rear direction relative to the fastener-abutment part, characterized in that the input-accepting part is configured to accept, as the setting information, setting information for an initial position of the pin-gripping part in the front-rear direction, the motor-control part is configured to control operation of the driving mechanism to move the pin-gripping part rearward from the initial position relative to the fastener-abutment part so as to pull the pin gripped by the gripping claws and deform the cylindrical part abutting on the fastener-abutment part, thereby fastening the workpiece between both end portions of the cylindrical part and tearing off the shaft part at the small-diameter part, and the motor-control part is further configured to control operation of the driving mechanism to move the pin-gripping part forward relative to the fastener-abutment part after the shaft part is torn off, and return the pin-gripping part to the initial position. a fastener-abutment part (61A; 61B) configured to abut on the cylindrical part; a pin-gripping (63A; 63B) part disposed to be movable along a driving axis relative to the fastener-abutment part (61A; 61B) and configured to grip a portion of the pin, the driving axis extending in a front-rear direction of the fastening tool; a motor; a driving mechanism configured to be driven by power of the motor to move the pin-gripping part (63A; 63B) rearward along the driving axis relative to the fastener-abutment part (61A; 61B), thereby fastening the workpiece via the fastener; an input-accepting part configured to accept setting information for a control condition of the motor, the setting information being inputted via an operation part (51; 55) configured to be externally operated by a user; and a motor-control part configured to control operation of the driving mechanism by controlling driving of the motor according to the control condition based on the setting information accepted by the input-accepting part, wherein the fastening tool is configured to use, as the fastener, a tear-off type fastener, in which the pin is inserted through the cylindrical part, the pin includes a shaft part having a small-diameter part for breakage, the pin-gripping part has a plurality of gripping claws configured to grip the shaft part, and is coaxially held within the fastener-abutment part so as to be movable in the front-rear direction along the driving axis relative to the fastener-abutment part, the pin-gripping part being configured such that its gripping force of gripping the shaft part changes as the gripping claws move radially relative to the driving axis along with a movement of the pin-gripping part in the front-rear direction relative to the fastener-abutment part, characterized in that the input-accepting part is configured to accept, as the setting information, setting information for an initial position of the pin-gripping part in the front-rear direction, the motor-control part is configured to control operation of the driving mechanism to move the pin-gripping part rearward from the initial position relative to the fastener-abutment part so as to pull the pin gripped by the gripping claws and deform the cylindrical part abutting on the fastener-abutment part, thereby fastening the workpiece between both end portions of the cylindrical part and tearing off the shaft part at the small-diameter part, and the motor-control part is further configured to control operation of the driving mechanism to move the pin-gripping part forward relative to the fastener-abutment part after the shaft part is torn off, and return the pin-gripping part to the initial position.