The present invention provides a light emitting unit that can accurately control the light output angle and/or direction over long period and an image taking apparatus provided with the light emitting unit. The light emitting unit has a light source, a reflector provided at the back surface of the light source and an optical member provided at the front of the light source. The optical member having: a container which is light-transmissive at least in a light passage region; a light-transmissive dispersion medium enclosed in the container; a dispersoid which is dispersed in the dispersion medium, which is light-transmissive, and which has a refractive index different from the refractive index of the dispersion medium. The optical member controls the output angle and/or direction of the light emitted from the light source and reflected by the reflector by moving the dispersoid using electromagnetic force.