The effects of sharpness of needle electode on the spark voltage in needle-plane and needle-needle spark gaps at atmospheric pressure was investigated experimentaly in this paper. As the sharpness of needle electrode increases, the spark voltage increases, and the rate of increase is greater in needle-needle electrode than in needle-plane gap. the effects of sharpness is greater in small gap length. These characteristics can be explained by the electric field strength at the needle tip depending on the sharpness of needle, electro-static capacity between the electrodes, and the polarity effect in needle-plane gap. These experimental results will be able to play an important roles on the design of needle-needle gap as high voltage measurement devices and of needle-plane gap as high voltage rectifier equipments.