EN
In this work we study the main differences between the superconducting properties of the Bi_4Sr_3Ca_3Cu_4O_x and (Bi_{0.8}Pb_{0.2})_4Sr_3Ca_3Cu_4O_x glass-ceramics. The Bi_4Sr_3Ca_3Cu_4O_x and (Bi_{0.8}Pb_{0.2})_4Sr_3Ca_3Cu_4O_x glass-ceramics prepared in the same conditions contain similar amounts of the superconducting 2212 phase, however their superconducting and normal-state electrical properties differ significantly. The main reason which makes BiSrCaCuO glass-ceramics worse superconductor than BiPbSrCaCuO is its microstructure.