A diffusing adhesive layer has a light-transmissible adhesive layer dispersively containing colorless light-transmissible particles so as to exhibit light diffusing characteristic. The light diffusing characteristic of the diffusing adhesive layer is not higher than 10% in terms of a light diffusion factor which is defined as 100.times.I.sub.30 /I.sub.10 when I.sub.30 is the intensity of light transmitted in a direction inclined by 30 degrees relative to a direction of perpendicular transmission of perpendicularly incident light, and I.sub.10 is the intensity of light transmitted in a direction inclined by 10 degrees relative to the direction of perpendicular transmission of perpendicularly incident light. Another diffusing adhesive layer has a total light transmission factor of not lower than 85% and a direct transmission factor of not higher than 30%. In an optical member, one of the diffusing adhesive layers is provided on an optical material having at least a polarizing plate or a retarder plate. In a reflection type liquid-crystal display device, the optical member and one of the diffusing adhesive layers are provided between a liquid-crystal cell and a polarizing plate.