The invention provides an input device having an illumination function, capable of illuminating the annular illumination portion provided in the operating member capable of the rotating operation and a plurality of the illumination portions, using the same light source. An operating knob (2) capable of a rotating operation that includes a first illumination portion (20) with an annular shape and a second illumination portion (30), is provided around the operating knob (2). The operating knob (2) is configured by a combination of an inner shaft body (6) made of a resin and a grip ring body (7), allowing the inner shaft body (6) to be fitted outward. A light shielding cap (8) is attached to a front end portion of the inner shaft body (6). A cylindrical light guide portion (6a) having the first illumination portion (20) in the front end face and a drive portion (6b) to be connected to a rotating shaft (10a) of a rotary encoder (10) are integrally molded in the inner shaft body (6), and a rear end face (6g) of the cylindrical light guide portion (6a) opposes a first light emitting face (5c) of a light guide member (5) over the entire periphery. A light incident face (5d) of the light guide member (5) opposes a light source (4) and the first and second illumination portions (20) and (30) are illuminated by light of the light source (4) via the light guide member (5).