A polycarbonate-based resin composition for extrusion molding using a siring die, and a molded product produced by extrusion-molding the resin composition using a sizing die, The polycarbonate-based resin composition comprises, as a main component, a polycarbonate having a viscosity-average molecular weight of 17000 to 27000 and containing main repeating units represented by the following formula (A): ##STR00001## wherein an amount of proton (Pa) and an amount of proton (Pb) per 1 g of the polycarbonate which are calculated from respective integral values of a signal (a) detected at .delta.=7.96 to 8.02 ppm and a signal (b) detected at .delta.=8.11 to 8.17 ppm in .sup.1H-NMR spectra thereof as measured in a deuterated chloroform solvent, satisfy the following formula (1): 4<{(Pa)+(Pb)}<26 (1) wherein a unit of each of (Pa) and (Pb) is .mu.mol/g. The above polycarbonate resin composition exhibits good mechanical properties and a good moldability.