In the reliability evaluation of facilities with quantitative characteristics of components, there is a case that these characteristics are connected one another from the lowest rank to highest one as hieranhical structure. In this case, considering the relative importances and relations of these characteristics, we have to do overall evaluation by means of input informations of the lowest rank. In this paper, an attemp is made to illustrate a linguistic expression of reliability of facilities, based on the fuzzy inference model. At first, the evaluation is Performed through such as linguistic variables as "safe","ordinary", "unsafe", etc.. Information of the linguistic variables is transmitted from the input events to the top event, in which weightening is taken into account on the evaluation of each element. The final result, which is obtained at the top event in the form of membership function, is interpreted by use of the concept of pattern recognition.