The heat flux and the thermal expansion of BaTiO 3 were simultaneously measured with a temperature resolution of milli-Kelvin to observe the multistage transitions. Heat flux was detected by the thermomodule and thermal expansion was detected by observing the change of capacitance due to the change of the sample length. At least six thermal anomalies were observed between 402 and 405 K in BaTiO 3 simultaneously in heat flux and thermal expansion in the cooling process. The correspondence of the anomalies observed in the two physical properties was excellent. The thermal expansion curves along 〈0 0 1〉 direction obtained at the cooling rates less than 20 μK s −1 consisted of several steps with different number and magnitude depending on the cooling rate. The hysteresis behaviors for the phase transition of BaTiO 3 are discussed in terms of domains.