A lens apparatus includes a first lens barrel member and a second lens barrel member coupled with the first lens barrel member via a cam mechanism. The first lens barrel member includes a stopper portion and a gear portion. The stopper portion comes into contact with a first contact surface formed in the second lens barrel member, when the first lens barrel member protruding from the second lens barrel member in the optical axis direction receives the external force from a front end side of the first lens barrel member in its protruding direction, to restrict a displacement of the first lens barrel member with respect to the second lens barrel member due to the external force. The gear portion comes into contact with a second contact surface formed in the second lens barrel member to restrict the displacement due to the external force.