Gas mixing apparatus are used for getting a mixture of various kinds and concentrations of gases. The problems with conventional apparatus are that the concentration and flow rate coverage is not so wide. When change in concentration of some elements are required, for example between 1ppm and 1%. Two or three channels are needed for the element. To prepare several kinds of gases, the system becomes complicated and costly. The new gas mixing apparatus from Fronto Co., Ltd. uses newly developed Super Flow Adjuster whose adjustable flow rate covers about 100,000 times, while conventional needle valves figure is about 100 times. The rotation number indicator shows precisely the valve opening position. With this rotation indicator Super Flow Adjuster, the flow rate of any gas between 0.1 mL/min and 10 L/min. can be adjusted.