Lens barrel of microscope objective

PROBLEM TO BE SOLVED: To improve productivity by reconsidering the structure of a lens barrel part from the viewpoint of the production error of optical parts and keeping the adjustment of an air space distance to the minimum. SOLUTION: In this lens holding device holding at least cemented lens components L1 and L2 and a lens component L3 separate from the cemented lens components along a specified optical axis Ax, the cemented lens components include at least a 1st lens L1 and a 2nd lens L2 cemented with the 1st lens; the outside diameter of the 1st lens L1 is made larger than that of the 2nd lens L2; the lens component L3 and the 1st lent L1 are arranged to put the 2nd lens L2 in between; a distance decision member 1 is provided, which is arranged to butt on the lens surface L1b on the 2nd lens side of the 1st lens L1 and the lens surface L3a on the 2nd lens side of the lens component L3 and decides the distance in an optical axis direction between the 1st lens L1 and the lens component L3; and ΣdL+dA = constant is satisfied when it is assumed that the sum total of the center thickness of the 2nd lens L2 is ΣdL and the distance between the 2nd lens and the lens component L3 is dA.