A method for making a BaTiO3-based dielectric having a high dielectric constant and a low dielectric loss wherein, a BaTiO3-based body is subjected to a pre-heat treatment in a hydrogen (H2) atmosphere or a reducing atmosphere containing mixed gas of hydrogen and nitrogen in a ratio of hydrogen:nitrogen=5 to 100%:0 to 95% prior to a sintering process in the manufacture of dielectrics, in order to obtain a reduced average grain size of BaTiO3. By virtue of the reducing average grain size of BaTiO3, a BaTiO3-based dielectric having a high dielectric constant and a low dielectric loss is obtained. This method provides an advantage in that it is possible to make a BaTiO3-based dielectric having a very small average grain size while having a high relative density in accordance with a simple heat treatment conducted for pure BaTiO3 or even for BaTiO3 added with an additive in a reducing atmosphere at a temperature less than a liquid phase forming temperature, prior to a sintering process for sintering the BaTiO3.