Abstract: The breakdown processes of the flute-type hollow cathode discharge was observed by a low-light level TV eamera of the SEM (Silicon Electron Multiplication) type, the most sensitive one of low-light level cameras of modern industry. An explantion for the mechanism of light developmen was presented. The light development was divided into two stages, i.e., the stage (1st stage) of self-sustained dark discharge developed in the space between the anode bar and the outer-side of the flute tube, and the stage (2nd stage) of entering of dischage through the hole into the flute tube. corresponding to the two stages, there are two -processes, one existing at the metal surface around the hble and the other at the inner surface of the cathode. According to the above results, a discussion on the current principle of the design of geometrical parameters of the flute type was given.