An electric fastener driver (1) having a compact size and simple construction. A driver segment (18) provided with a rack is movably disposed in a housing (2). A flywheel (9) is driven by a motor (8). A drive shaft (10) is concentric with and integral with the flywheel. A coil spring (11) is fixed to the drive shaft. A driven rotor (12) is coaxial with the drive shaft and has one end portion serving as a spring seat (12B) portion positioned within the coil spring. A pinion (12C) is disposed at the driven rotor and is meshedly engaged with the rack (18A). An urging section (14) is disposed within the driven rotor. A ball (16) is movably disposed in a through-hole formed in the driven rotor for urging an end portion of the coil spring by the urging section. A solenoid (13) controls a protruding amount of the ball from the surface of the driven rotor.