The object is to easily expand a variable range of selective wavelengths without enlarging a device. A spectral device 1 of the present invention includes four band pass filters 11a to 11d through which a light L2 from a light source 3 is selectively transmitted within a wavelength range according to an incident angle of the light L2, and a tabular rotary table 10 in which the band pass filters 11a to 11d are installed upright on a principal surface 10a, and which is made rotatable around a rotational center C1 along the principal surface 10a, and the four band pass filters 11a to 11d are respectively disposed so that optical incidence planes 12 or optical emission planes 13 are inclined with respect to lines connecting the rotational center C1 on the principal surface 10a of the rotary table 10 and center points 15a and 15d of the bandpass filters 11a to 11d.