To provide a power driver mounting type bit holding device which allows an operator to discriminate each bit at a glance and to quickly and easily connect a necessary bit to a power driver.

The bit holding device has a body which holds a shaft having a bit mounting port in one end thereof, so as to be rotatable in a circumferential direction but locked in an axial direction. Then the body has a plurality of movable arms arranged thereon around the shaft like a ring. The arms have the bits of various types rotatably mounted thereon.