To provide an objective lens drive unit which can be thinned (miniaturization) while achieving various adjusting operations of an objective lens.

The objective lens drive unit 1 includes an objective lens 11, a lens holder 12, a movable part for movably holding the lens holder 12, and a movable part fixing base plate 16 erected on a base 14 and configured to fix the movable part. The movable part includes an even number, six or more, of elastic supports 17, and is fixed to the movable part fixing base plate 16 via a spacer member 15 by the elastic supports 17. Among the even number of elastic supports 17, the ends of the four elastic supports 17 are connected to the movable part fixing base plate 16 to form a linearly symmetrical rectangle sandwiching a center line in the erection direction of the movable part fixing base plate 16 on the base 14. The ends of the remaining elastic supports 17 are connected to the movable part fixing base plate 16 outside the four sides of the rectangle and in a position deviated from the extension line of the side parallel to the center line.