Violet tungsten oxide is prepared with pure ammonium paratungstate in the argon gas. Tungsten powder is obtained with violet tungsten oxide through deoxidation in the hydrogen gas (Rate of purity: 99.99 %, dew point: -40 °C), and tungsten powder is oxidized in the air. Tungsten oxide is reduced with tungsten powder in the hydrogen gas. The samples are characterized with the laser particle size distribution measuring instrument and field-emission scanning electron microscope. The results show that ultrafine tungsten powder is obtained through circulatory oxidation twice and reduction three times. The percentage of the particle size distribution of ultrafine tungsten powder is 95.73 % between 0.1 μm and 1.0 μm.