A solid electrolytic capacitor including: an anode containing a valve metal or its alloy; a dielectric layer provided on the surface of the anodic; a cathode provided on the surface of the dielectric layer; and an outer package resin covering the anode, the dielectric layer and the cathode, wherein a glass transition temperature (Tgb) of the outer package resin is a temperature ranging from 0.50 to 0.90 times a maximum glass transition temperature (Tga) which is a maximum value of glass transition temperatures exhibited by the outer package resin after each heat treatment at variable temperatures of every 10° C. from 50° C. to 200° C. (treatment time: 5 hours) which is performed on the outer package resin before a curing process.