A lens apparatus and image pickup apparatus thereof. The lens apparatus includes a first fixed lens-barrel with fixed-side first guide grooves and fixed-side second guide grooves, a first movable lens-barrel arranged at the outside of the fixed lens-barrel, movable-side first guide grooves, a second movable lens-barrel arranged at the inside of the fixed lens barrel, and movable-side guide grooves. Three first rolling element units are provided between the fixed-side guide grooves and the movable-side first guide grooves, and three second rolling element units are provided between the fixed-side second guide grooves and the movable-side second guide grooves. The first movable lens-barrels and the second movable lens-barrels are supported to the one-group lens and the two-group lens in such a manner that they can be independently moved in the optical axis directions of the first and second lenses.