Provided is an illuminating device capable of preventing a light guide plate from being shaved because of contact with a fixation member on a back face side of an end portion of the plate. The illuminating device includes alight guide plate (11), a chassis (14) housing the plate and including a bottom plate (14a), and a light source holding member (15) fixed to the bottom plate by a fixation screw (16) and holding a light source (21) close to a light entrance face (11a) of the light guide plate, and further includes a concave portion 12 preventing contact between a screw head (16a) of the screw and the light guide plate and disposed on a back face of an end portion (11d) of the light guide plate at a position where the head is to be disposed if the screw is disposed on a side of the back face.