PURPOSE: To provide a lens unit for a camera-integrated VTR excellent in resolution and an aperture device constituting it and to attain a photographed image with excellent quality and excellent focusing performance by forming the opening section side end section of the plate-like member of the aperture device into the shape recessed at the center section.

CONSTITUTION: The aperture vane 1 of an aperture device 4 is cut into a dog-legged shape at the center section when an opening section is formed, and an aperture vane 2 is cut into a dog-legged shape in the opposite direction to the aperture vane 1 at the center section of the portion forming the opening section. The opening section side end section of a neutral density filter 3 is cut into a dog-legged shaped at the center section in the same direction as the aperture vane 2. When the transmitted light quantity is desired to be made very small, no slit-like shape is formed at the opening section end by the aperture vane 1 and the neutral density filter 3, and the diffraction phenomenon of light generated by the conventional aperture device can be prevented.