The present invention provides high strength spring and high strength spring steel wire superior in corrosion fatigue characteristics and methods of production of the same, that is, a high strength spring steel wire and high strength spring containing, by mass%, C: 0.35 to 0.50%, Si: 1.00 to 3.00%, and Mn: 0.10 to 2.00%, restricting P to 0.015% or less and S to 0.015% or less, having a balance of Fe and unavoidable impurities, and, when raising the temperature in the range from 50°C to 600°C by 0.25°C/s and measuring the differential scanning calories, having the only peak of the exothermic reaction present at 450°C or more. A method of production of high strength spring characterized by tempering under conditions where the tempering temperature T[K], tempering time t[s], and content Si% [mass%] of Si satisfy the following: 16000‰¤(T-40×[Si%])×(31.7+logt)‰¤23000.
