BACKLIGHT DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

A liquid crystal display device with high visibility and a backlight device for implementing the liquid crystal display device are provided. A backlight device () for irradiating light to a back surface of a liquid crystal panel () in a liquid crystal display device includes: light sources (); a substrate (); and a plate-like optical member () through which a part of light emitted by the light sources () is transmitted. The optical member () includes: first region (A) and two or more second regions (A), wherein in the first region (A), the light transmittance increases as separating from a mounting position of one light source (), and in the second regions (A), the light transmittance increases as approaching an outer peripheral portion from a central portion of the optical member () in a predetermined direction in places in contact with another adjacent second region (A).