Pyroelectric energy harvesting has been attracting increasing attention due to its abundance and potential applications. In this work, we comparably investigated the pyroelectric properties of Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 bulk ceramics without (PNZT95/5) and with Mn doping (PNMZT95/5). Compared to PNZT95/5, PNMZT95/5 demonstrated a lower dielectric constant and low rhombohedral - high rhombohedral ferroelectric phase transition temperature (TLH from 37 °C to 27 °C). Moreover, the poling time displayed significant effects on the dielectric and pyroelectric properties of the ceramics. A giant pyroelectric response was obtained for the PNMZT95/5 ceramics, of which the maximum pyroelectric figure of merit FE was 16017 J/(m3K2) after 180 min of poling, which increased 62% compared with the FE for PNZT95/5 (9890 J/(m3K2), far higher than those of other pyroelectric materials as well. PNMZT95/5 ceramics is suggested to be a promising candidate for the thermal energy harvesting applications.