Patent ID: 8360965

Claim:
An endoscopic image pickup unit which, being fixedly fitted in a distal end body of an endoscope by a fixing member, can change optical characteristics of an objective optical system, the endoscopic image pickup unit comprising: a first fixed lens frame which holds a first objective lens group; a second fixed lens frame which holds a second objective lens group; a movable lens frame which, being installed in the second fixed lens frame so as to be able to move forward and backward along a photographic optical axis, holds a movable lens; and a deformation preventing member which, being interposed between the distal end body and the second fixed lens frame and being fixedly fitted over an outer periphery of a distal end of the second fixed lens frame in a state of being sandwiched between the first fixed lens frame and the second fixed lens frame, prevents the second fixed lens frame from being deformed by fixing force of the fixing member when the endoscopic image pickup unit is fixed to the distal end body, wherein the deformation preventing member is fitted over the distal end body by the fixing member abutting a flank of the deformation preventing member, and prevents deformation of the second fixed lens frame by abutting the first fixed lens frame so as to reduce deformation in an inner direction due to a fixing force by the fixing member, the deformation preventing member including a rib having an inward flange shape so as not to restrict forward and backward movements of the movable lens frame which holds the movable lens in the second fixed lens frame, the rib extending in a radially inward direction.