A vehicle occupant detection device (10) includes light-receiving elements (CMOS element 33) for receiving light from a vehicle interior, and a signal processing part (12) for processing a signal detected by the light detecting elements. A vehicle occupant in the vehicle interior is detected by the signal detecting part on the basis of an image signal obtained by the light-receiving elements. The vehicle occupant detection device has a band-pass filter (35), which has a frequency range whose transmission band (52) is substantially the same as a sunlight absorption spectrum band (62), and in which a wavelength of the light received by the light-receiving element is selected according to the transmission band. An object that is to be detected and is present in the vehicle interior is accordingly imaged/detected by the vehicle occupant detection device using a certain wavelength region of near infrared light, and decreases in contrast in relation with sunlight are eliminated.