he principle and optional conditions of inert gas fusion (impulse heating) method for determination of hydrogen with Sn-flux are described. The results show that the method for determinating hydrogen in Ti. Zr. Hf. Ta. Nb and their alloys is accurate. The POwer for analysing are 2500W for Ti. Zr and Hf and 2700-2800W for Ta and Nb. The heating-times are 30s for Ti. Zr and Hf and 40s for Ta and Nb, respectively.