A lens apparatus has an image pickup optical system including a focus lens and a zoom lens, a focus detector, a defocus amount calculating unit, and a controller. The focus detector detects a focus state of the image pickup optical system. The defocus amount calculation unit calculates a defocus amount based on the detected focus state. The controller calculates a driving amount necessary to drive the focus lens to a focus position based on the calculated defocus amount. The controller controls the driving of the focus lens. In particular, the controller controls a driving speed of the focus lens depending on the calculated defocus amount and the calculated driving amount.