1. A defuzzifier circuit comprising: a weighted summing circuit means for receiving electric signals from a plurality of lines representative of fuzzy information distributed over said plurality of lines, multiplying said signals by respective values corresponding to grades of said lines and summing the multiplied values, said weighted summing circuit means having an output; a simple summing circuit means for receiving said electric signals, modifying said electric signals without weighting and summing said modified signals, said simple summing circuit means having an output; a constant-current source means for supplying a constant current to said output of said simple summing circuit means; and connecting means connecting said output of said weighted summing circuit means with said output of said simple summing circuit means for equalizing an output voltage of said simple summing circuit means with an output voltage of said weighted summing circuit means.