A lens device comprises an optical system including a first lens which performs a magnification varying operation, and a second lens which is positioned rearwardly of the first lens along an optical axis and performs a focus adjusting operation, a first detecting circuit for detecting a position of the first lens and a position of the second lens, and a storage circuit which stores a positional relation between the first lens and the second lens under reference conditions, wherein a position detection by the first detecting circuit is corrected by use of deviation information if the position of the first lens and the position of the second lens detected by the first detecting circuit deviate from the positional relation stored in the storage circuit, when an in-focus state of the second lens is detected.