We present a new micro optical devices, dynamic focusing lens (DFL) using a multi-layered piezoelectric bimorph micro actuator. DFL is structured to directly deform the lens shape as a crystalline lens of the human eye. The deformable lens is comprised of two thin glass diaphragms with a transparent working fluid sealed between them. The curvature of the lens shape is changed according to the applied voltage of the actuator. DFL shows quick response up to 150 Hz for focal plane shift because the mass movement can be minimized compared with the conventional focusing method of moving a lens position. We also propose digital all-in-focus microscope system as an application of DFL. This system realizes real-time observation for micro parts assembling with a deep depth of field, as well as three-dimensional shape measurement using only one image sensor. In this paper, a newly developed real-time algorithm called one pixel method for generating clear image having a deep depth of field is described. This method is able to process one original picture (640 x 480 pixels per frame) in approximately 1.0ms. Results of three-dimensional shape measurement in high accuracy using the contrast of brightness method are also discussed.