To reduce labor of a worker performing tightening/loosening work of a bolt and nut and to reduce an exposure amount.

This device comprises a rotational torque imparting mechanism 2 imparting rotational torque to a bolt or nut to be tightened; a pair of support shafts 3, 3 vertically turnably supporting this rotational torque imparting mechanism 2; a hoist 4 for suspending the rotational torque imparting mechanism 2 in a crane equipment through these support shafts 3, 3; oscillating drive mechanism 15 ascillatingly driving the rotational torque imparting mechanism 2 around the support shaft 3, 3; and a tilt adjustment mechanism 16 adjusting tilt of the hoist 4.