To provide an exposure device, which can form a clearance of black color absorbing layers or a phosphor layer into the shape hard to generate a distortion over the whole of a fluorescent surface by providing two or more of light source parts.

A light source unit 30 is provided under a support base 19 for positioning a panel 1, which forms a case part of a color cathode-ray tube. An optical lens system 21 for approximating the light, which is emitted from the light source unit 30, to the path of an electron beam emitted from an electron gun of a color cathode-ray tube and a correcting filter 22 for correcting the distribution of quantity of light in the inner surface of the panel 1, which is positioned by the support base 19, are arranged over the light source unit 30. In the light source unit 30, two linear light sources 31a, 31b such as straight tubular extra-high pressure mercury lamps are arranged in the direction of the panel 1. These two light sources 31a, 31b are arranged so as to obtain patterns, which are displaced and overlapped with each other in the radiating direction of the panel 1. Quantity of light is thereby increased, and a fluorescent surface, which can shorten the time to be required for burning of pattern and which is hard to produce the deterioration of color purity, can be formed.