A zoom lens barrel capable, even if it has an image shake correction mechanism and a diaphragm mechanism, of decreasing a distance between lens groups of a photographing optical system of the lens barrel, whereby the lens barrel size can be reduced and the magnification can be increased, and capable of preventing a collision between diaphragm blades of the diaphragm mechanism and the lens groups from occurring when vibration, impact, or the like is applied to the lens barrel. When apart of an image shake correction lens intrudes into an aperture of diaphragm blades, a restricted portion of a lens holding member and a restricting portion of a diaphragm restrict a maximum movement of the lens holding member in a direction perpendicular to the optical axis, thereby restricting a maximum amount of movement of the image shake correction lens in the direction perpendicular to the optical axis.