An object of the present invention is to provide a chromoprotein derived from Cnidopus japonicus. The present invention provides a chromoprotein derived from Cnidopus japonicus having the following properties: (1) the absorption maximum wavelength is 610 nm, and fluorescence is not emitted; (2) the molar absorption coefficient is 66,700 at 610 nm; and (3) the pH sensitivity of light-absorbing property is stable at between pH 4 and pH 10.