We successfully examined effects of pulverization and an addition of sintering aids on the orientation degree, sintering performances, and dielectric properties of sintered compacts of needle-like TiO 2 particles. In the case of additive-free samples, an improvement in sintering performances was achieved by pulverization. However, the orientation degrees of these samples were decreased and calcination at high temperatures (≥ 1200 °C) was indispensable for obtaining an adequate relative density. On the other hand, by the addition of CuO-TiO 2-Nb 2 O 5-Ag 2 O type additives, the samples could be well sintered as much as 380 °C below their original sintering temperature with retaining the high orientation degrees. Moreover, high insulation resistances were achieved for samples with additives compared to that of additive-free samples and its relationship with the microstructures was discussed. Thus, this study provides an experimental investigation on improvements of sinterabilities and insulation properties of orientated TiO 2 ceramics by the use of sintering additives.