An optical sheet member includes a polarizing plate including a 
polarizer (A); an optical conversion member (D); and a brightness enhancement film including a reflection 
polarizer (B), in which the brightness enhancement film has a reflection center 
wavelength range of 400 nm to 500, and the optical conversion member (D) converts a part of 
blue light which is transmitted through 
polarizer (B) and is incident on the optical conversion member (D), and has an emission center 
wavelength range of 400 nm to 500 nm and which has an emission center 
wavelength range of 500 nm to 600 nm and 
red light which has an emission center 
wavelength range of 600 nm to 700 nm, and transmits a part of the 
blue light. When the optical sheet member is incorporated in an 
image display device, front brightness, contrast, and a color reproducing region are enhanced, and color unevenness is reduced.