A fastening tool includes a bolt-gripping part, an anvil, a bolt-gripping-part driving mechanism, a motor, a housing, and thrust rolling bearings. The bolt-gripping-part driving mechanism includes a first mechanism part supported by the housing and a second mechanism part connected to the bolt-gripping part. The second mechanism part is configured to be driven in a longitudinal-axis direction by the first mechanism part being rotationally driven, so that the bolt-gripping part is moved in the longitudinal-axis direction relative to the anvil. The thrust rolling bearings are disposed on a first direction side and a second direction side of the first mechanism part, respectively.