Abstract: A solid electrolyte capacitor comprises a capacitor element disposed in a case, and a rubber seal member tightly fitted in an upper opening of the case, with lead terminals projecting from the element and extending through the seal member. To fabricate the capacitor, a TCNQ complex salt is placed into a heating box and melted by heating. The capacitor element is placed into the box, impregnated with the complex salt, then immediately withdrawn from the box and cooled in air to solidify the salt by cooling. Subsequently, the lead terminals of the element are inserted through the seal member. The element is placed into the case which has approximately the same diameter as the heating box, with the seal member attached to the element, and the case is constricted to seal off its opening, whereby the solid electrolyte capacitor is obtained.