A zoom lens barrel is intended to ensure precision in dimensions for a cam groove and contribute to realization of a compact and lightweight design and reduction in cost of manufacturing. The zoom lens barrel has a cam cylinder that is a cam member having a first cam groove and second cam groove, and a lens frame having a first cam pin to be engaged with the first cam groove, and a second cam pin to be engaged with the second cam groove. When the first cam pin formed on the lens frame moves along the first cam groove, the lens frame moves over a power varying zone that is a first zone in the direction of an optical axis. When the second cam pin formed on the lens frame moves along the second cam groove, the lens frame moves over a collapsing zone that is a second zone in the direction of the optical axis.