Abstract: An area lighting device has straight fluorescent lamps (3) arranged side by side at regular intervals, a signboard panel (4) adjacent to front curved faces of the lamps, and a flux regulating cover (5) detachably attached to a frontal curved surface of each lamp. The cover is a split half of a heat-resistant elastic cylinder. A reflective plate (8) in rear of each lamp (3) has a pair of longitudinal crests (9) adjacent to the back face of each lamp so that these crests prevent light beams from scattering sideways from the rear middle region of the lamp, thus reflecting them forwards.