To provide an adjusting unit which makes it possible to easily operate a rotational effect filter while peeping in a viewfinder with a camera lens hood attached on a lens barrel part without spoiling the original function of the camera lens hood mounted on the lens barrel of a camera.

The adjusting unit is freely attached and detached at one of circumferential positions of the camera lens hood and can be engaged with the rotational effect filter at a proper position. Various problems are solved by providing the adjusting unit for the rotational effect filter for a camera lens characterized in that a rotary filter adjusting dial, a rotary handle for driving the rotary filter adjusting dial, and an adjustment moving dial for engaging the rotary filter adjusting dial with the rotational effect filter are constituted on a rack part and various rotational effect filters can easily be adjusted by transmitting rotation from the adjustment moving dial and rotary handle.