A rotating axis supporting device of the present invention includes: a housing; a rotating axis rotatably pivoted to the housing; a case for fixing the housing; and an adjustment mechanism adjusting a position of the rotating axis by causing an attachment surface of the housing attached to the case to be perpendicular to an axial direction of the rotating axis, attaching the housing to move relative to the case in parallel to the attachment surface, and moving the housing and the case relative to each other in parallel to the attachment surface.