This paper presents a system analysis to study function and failure of snow melting machines. Since the snow melting machine has short history of about ten years for its development, the systematic design guideline has not been established well in order to shorten the development period and respond to diversify of the needs. Based upon such technical needs, an analysis is made first to clarify the function of the snow melting machine and express directional graphs of the model by the ISM and DEMATEL methods. Secondly, six hundred sets of data on malfunction of the machine are analyzed by using the matrix chart and co-relations existing among various types of malfunction are discussed.