To obtain a zoom lens barrel which achieves shortening of housing length by moving a variable aperture stop mechanism in an optical axis direction to contribute to shortening of the housing length with simple constitution.

In the zoom lens barrel, an aperture control lens group is supported by a first lens moving frame, and the variable aperture stop mechanism to change an open aperture F value in accordance with a focal length is supported in the first lens moving frame to relatively move to the aperture control lens group in the optical axis direction, then the variable aperture stop mechanism is biased to move forward by a first energizing means. When the first lens moving frame and a second lens moving frame located in front of the first lens moving frame and relatively moving to the first lens moving frame in the optical axis direction are moved from a zoom photographing position to a housing position, the variable aperture stop mechanism is pressed by the second lens frame and moves to approach the aperture control lens group against the first energizing means, and a second energizing means which biases the second lens moving frame and the variable aperture stop mechanism in a direction where they separate from each other and whose energizing force is weaker than the first energizing means is interposed between the second lens moving frame and the variable aperture stop mechanism.