A thorough study has been made of the physical properties under high pressure of the perovskite BaRuO3 synthesized under pressure; it includes the critical behavior in the vicinity of Tc to 1 GPa and the temperature dependences of resistivity and ac magnetic susceptibility up to 8 GPa. The ferromagnetism in BaRuO3 is suppressed at 8 GPa. Critical fluctuations in the vicinity of Tc have been found in BaRuO3 and they are enhanced under pressure. These observations are in sharp contrast to SrRuO3 where mean-field behavior is found at Tc.