As a sintering aid for Y-doped BaTiO3 ceramics, BN and BaB2O4 compounds were chosen, and then sintering behavior and PTCR properties of specimens were investigated with the addition of each boron source. Of the various boron source compounds, BaB2O4 greatly lowered the densification starting temperature by the formation of liquid phase around 900 degrees C, lowered room temperature resistivity and improved PTCR effect of specimens. When boron components were added to BaTiO3 ceramics, the mixture of amorphous and crystallized BaB2O4 particles were located at triple junction of solid grains. On the other hand, there existed an amorphous thin film of 3 nm thickness at the two grain junction region.