The invention discloses an adjustable-slit exposure device. The exposure device comprises a first member, a second member and a rough adjustment mechanism, wherein the first member is provided with afirst arc surface, the second member is provided with a second arc surface, the first arc surface and the second arc surface are opposite to each other, a slit is defined between the first arc surfaceand the second arc surface, and the rough adjustment mechanism can be used for driving one of the first arc surface and the second arc surface to adjust the width of the slit. According to the exposure device, the distance between the first member and the second member is adjusted by the rough adjustment mechanism so as to adjust illumination of the exposure device, the width of the slit can be adjusted, the illumination of the exposure device is adjusted, the illumination and the resolution are equalized, and the resolution requirement of a product is met; and moreover, the exposure device is not needed to be disassembled during adjustment of the width of the slit, the yield is saved, and the production efficiency is improved.