The utility model provides a PAS type nitrogen producing device which is higher in yield and capability, smaller in size and more power-saving compared with the prior art. The nitrogen producing device provided by the utility model is used for producing nitrogen from raw material gas in the manner of pressure swing adsorption. The device is characterized by comprising a compressor, two main absorption grooves and a subsidiary absorption groove, wherein the compressor is used for compressing the raw material gas; the two main absorption grooves are filled with a first adsorbent; and the subsidiary absorption groove is arranged on a pipeline connected between the two main absorption grooves, and is filled with a second adsorbent for reducing the concentration of oxygen in the gas, and the volume of the subsidiary absorption groove is less than that of the main absorption grooves by 1/40 to 1/5.