Dense CaRuO 3 body was synthesized by spark plasma sintering (SPS) using CaCO 3 and RuO 2 powders. The second phases of CaO and RuO 2 were identified at the Ru to Ca molar ratio in the source powder (R Ru/Ca ) of 0.5 to 0.8 and at R Ru/Ca ¼ 1:1 to 1.4, respectively. A nonstoichiometric solid solution range of bulk CaRuO 3 body was first found in the R Ru/Ca range between 0.7 and 1.0. The density increased with increasing R Ru/Ca and the highest density was 97% at R Ru/Ca ¼ 1:4. The electrical conductivity () decreased with increasing temperature, showing a metallic conduction behavior. The increased from 1 Â 10 5 to 5 Â 10 5 Sm À1 with increasing R Ru/Ca at room temperature (RT). The Seebeck coefficient (S) was around 25 to 35 VK À1 from RT to 1023 K independent of composition, exhibiting a p-type conduction. The thermal conductivity () slightly increased with increasing temperature and showed the lowest value at R Ru/Ca ¼ 1:0. The dimensionless figure of merit (ZT) had the maximum at R Ru/Ca ¼ 1:1, and the highest ZT value was 0.034 at 1020 K.