For accurate holding, easy attachment and detachment, and sufficient rotation force, a rotary tool has a holding and transmitting part 1 to hold a hexagonal column of a rotated body and give rotation force, comprising a recessed part 2, which has an inner face having an approximately regular triangle cross sectional shape, run-off parts 2a at corners of the triangle shape, and a uniform shape in depth direction, and plate springs 3, which are fixed at a bottom of the recessed part 2 and have pawl parts 3a at tips thereof positioned at the opening side of the recessed part 2, and the pawl parts 3a can be moved into the run-off parts 2a while contacting to three side faces of the hexagonal column H and generate spring force, when the hexagonal column H is inserted into the recessed part 2.