A defuzzification method is an important performance factor in fuzzy logic controllers (FLCs). When an FLC uses multishaped output fuzzy sets, existing defuzzification methods have the fat shape dominance phenomenon. The authors propose a new defuzzification method for multishaped output fuzzy sets. The method takes the degree of certainty on the fired level into account in the defuzzification process. Simulation experiments with a nonlinear plant show that an FLC employing the proposed defuzzification method is more stable and robust than existing FLCs.