Abstract: A fastener driving tool includes a frame defining therein an accumulator that accumulates compressed air, a cylinder, a piston movable between a top dead center and a bottom dead center, a main valve section having a main valve movable between a top dead center and a bottom dead center to alternately open and block fluid communication between a piston upper chamber and the accumulator, a trigger valve section having a plunger movable between a top dead center and a bottom dead center so as to alternately open and block fluid communication from the accumulator to a main valve chamber, and fluid communication from the main valve chamber to atmosphere, and a trigger adapted to press the plunger when operated by a user. The piston moves from the top dead center to the bottom dead center within 11.3 msec when the plunger is pressed.