An aromatic polycarbonate resin composition which is excellent in mechanical strength, suitability for transfer, light transmission, thermal stability, and moldability and can be molded into a thin or large molding; and a lightguide plate comprising the resin composition. The aromatic polycarbonate resin composition for lightguide plates comprises: an aromatic polycarbonate resin which has a viscosity-average molecular weight of 13,000-15,000 and in which the ratio of the weight-average molecular weight as determined by gel permeation chromatography in terms of polystyrene to the number-average molecular weight determined likewise, Mw/Mn, is 1.5-2.7; and a stabilizer and a release agent incorporated in the resin.