An object of the present invention is to provide a polycarbonate copolymer having excellent heat resistance and dimensional stability and heat resistant parts comprising the copolymer and suitable for use in various applications. The present invention is a polycarbonate copolymer comprising 5 to 95 mol % of recurring unit (component a) represented by the following general formula (I): ##STR00001## and 95 to 5 mol % of recurring unit (component b) represented by the following general formula (II): ##STR00002## (wherein R.sup.a to R.sup.d are each independently a hydrogen atom, a hydrocarbon group which may contain an aromatic group having 1 to 9 carbon atoms or a halogen atom, and W is a single bond, a hydrocarbon group which may contain an aromatic group having 1 to 20 carbon atoms or an O, SO, SO.sub.2, CO or COO group), and various heat resistant parts comprising the copolymer.