RF-DC plasma nitriding system has been developed as an alternative surface treatment. Through comparison of its nitriding performance for SKD-61 tool steels with the commercial plasma processes, the highest hardness depth profile was attained: e.g. the surface hardness > 1200 Hv and the nitrided thickness > 60 µm were attained after nitriding for 14.4 ks at 753 K. In the present papers, two distributed plasma nitriding systems were developed to propose a miniature surface treatment for manufacturing on the basis of this RF-DC plasma nitriding. The distributed multi-reactor system stood on the down-sized unit to make plasma nitriding in the parallel manner together with improvement of nitriding performance; e.g. the same nitriding performance for 14.4 ks in the above was fulfilled only for 7.2 ks. This down-sizing significantly reduced the total leading time in batch. The distributed multi-device system stood on the hollow cathode device working in the large-scaled nitriding chamber. Higher hardness and deeper nitrided layer thickness were obtained even by low temperature plasma nitriding for shorter duration; e.g. the surface hardness > 1400 Hv, the nitrided thickness > 40 µm and the higher nitrogen content > 4 mass% were put into practice by nitriding only at 693 K. Channels and holes in the micro-tube and micro-nozzles worked as a hollow cathode device; inner surface and holes of micro-parts were nitrided to have sufficient hardness.