A stylus (100, 100A, 100B, 100C, 100D) for use in conjunction with an electronic apparatus, the stylus (100, 100A, 100B, 100C, 100D), comprising: a trigger signal generating circuit; an optical sensor detecting incident light; a memory circuit storing color information of the incident light detected by the optical sensor; a color presenting circuit; a radio transmitting circuit transmitting the color information stored in the memory circuit to the electronic apparatus; a radio receiving circuit receiving a signal from the electronic apparatus; and a control circuit (12, 311, 403); the color presenting circuit being disposed in a pen tip portion of the stylus (100, 100A, 100B, 100C, 100D); the control circuit (12, 311, 403) detecting the color information by the optical sensor and controlling the color presenting circuit so as to present the color information in response to a trigger signal of the trigger signal generating circuit; when transmitting the color information detected by the optical sensor to the electronic apparatus via the radio transmitting circuit, the control circuit (12, 311, 403) controlling the color presenting circuit so as to make presentation different from color presentation at a time of detecting the color information by the optical sensor, wherein when a signal transmitted from the electronic apparatus in response to the transmission of the color information to the electronic apparatus is received via the radio receiving circuit, the color presenting circuit disposed in the pen tip portion of the stylus (100, 100A, 100B, 100C, 100D) is controlled so as to make presentation different from presentation at a time of the transmission of the color information to the electronic apparatus via the radio transmitting circuit, and wherein when transmitting the color information to the electronic apparatus via the radio transmitting circuit, the control circuit (12, 311, 403) performs control so as to blink the color presenting circuit disposed in the pen tip portion of the stylus (100, 100A, 100B, 100C, 100D), and when the signal transmitted from the electronic apparatus in response to the transmission of the color information to the electronic apparatus is received via the radio receiving circuit, the control circuit (12, 311, 403) controls the color presenting circuit so as to change the blinking to continuous lighting. a trigger signal generating circuit; an optical sensor detecting incident light; a memory circuit storing color information of the incident light detected by the optical sensor; a color presenting circuit; a radio transmitting circuit transmitting the color information stored in the memory circuit to the electronic apparatus; a radio receiving circuit receiving a signal from the electronic apparatus; and a control circuit (12, 311, 403); the color presenting circuit being disposed in a pen tip portion of the stylus (100, 100A, 100B, 100C, 100D); the control circuit (12, 311, 403) detecting the color information by the optical sensor and controlling the color presenting circuit so as to present the color information in response to a trigger signal of the trigger signal generating circuit; when transmitting the color information detected by the optical sensor to the electronic apparatus via the radio transmitting circuit, the control circuit (12, 311, 403) controlling the color presenting circuit so as to make presentation different from color presentation at a time of detecting the color information by the optical sensor, wherein when a signal transmitted from the electronic apparatus in response to the transmission of the color information to the electronic apparatus is received via the radio receiving circuit, the color presenting circuit disposed in the pen tip portion of the stylus (100, 100A, 100B, 100C, 100D) is controlled so as to make presentation different from presentation at a time of the transmission of the color information to the electronic apparatus via the radio transmitting circuit, and wherein when transmitting the color information to the electronic apparatus via the radio transmitting circuit, the control circuit (12, 311, 403) performs control so as to blink the color presenting circuit disposed in the pen tip portion of the stylus (100, 100A, 100B, 100C, 100D), and when the signal transmitted from the electronic apparatus in response to the transmission of the color information to the electronic apparatus is received via the radio receiving circuit, the control circuit (12, 311, 403) controls the color presenting circuit so as to change the blinking to continuous lighting.