This paper proposes a fuzzy functional inference method in which the consequent parts of the T-S inference method is generalized to fuzzy functions. Moreover, this paper addresses equivalence of the proposed fuzzy inference method. Namely, the fuzzy functional inference method is shown to be equivalent to the weighted T-S inference method whose consequent parts have weights, by adopting as the weight the area or the base length of fuzzy set obtained from the fuzzy function in the consequent part.