Using samples prepared by the same method as for a previously prepared 10% burnup sample, heat capacities and electrical conductivities of UO2 doped with simulated fission products equivalent to 2 and 5 at% burnup were measured simultaneously with a direct heating pulse calorimeter over the range 290-1500 K to confirm the presence of an anomalous increase in the heat capacity curve of UO2 doped with 10% simulated fission products previously found by the present authors. In addition, using a new sample of UO2 doped with 10% burnup simulated fission products prepared by a different method and, having better homogeneity of the dopants in UO2 than the previous samples, measurements of heat capacity and electrical conductivity were carried out in order to investigate the effect of different sample characteristics on the heat capacity anomaly. An anomalous increase in the heat capacity curve was seen in each sample, and those of two 10% burnup UO2 samples were much the same, indicating that the anomalous increase in inherent and does not depend on the sample character. The origin of the heat capacity anomaly was also discussed in comparison with that of UO2 doped with a single kind of cation reported previously.