A stage device includes a base and a stage movable portion that is movable along a surface of the base. An interferometer measures a position of the stage movable portion using measurement light. At least one of a piping element and a wiring element are connected to the stage movable portion. An auxiliary member, including a plurality of members connected with each other along an axial direction of the piping element, guides a bend of the at least one of the piping element and the wiring element. A plurality of heat insulating sheets are supported by the plurality of members of the auxiliary member. The plurality of heat insulating sheets are provided between a space through which the measurement light of the interferometer passes, and the at least one of the piping element and the wiring element.