Backlight module and stereo display apparatus

A backlight module including a beam splitting film, a light guide plate, and two light emitting elements is provided. The beam splitting film includes a light transmissive plate and multiple strip-shaped protrusion structures. Each of the strip-shaped protrusion structures has a first inclined surface group and a second inclined surface group. The first inclined surface group includes a first inclined surface and a second inclined surface with different slopes. The second inclined surface group includes a third inclined surface and a fourth inclined surface with different slopes. The light guide plate is disposed beside the beam splitting film. The two light emitting elements are respectively disposed at two opposite sides of the light guide plate and capable of flickering alternately. A stereo display apparatus is also provided.