To provide a comparatively inexpensive plate spring capable of improving fatigue strength, yielding strength, shape precision such as camber (curvature), and corrosion resistance by quenching a surface part again in addition to heat treatment performed usually and to provide its manufacturing method.

In this manufacturing method for the plate spring, high frequency quenching is applied to a face on a side on which tensile stress acts while applying load in the same direction as a use condition on a plate spring basic member on which predetermined heat treatment is applied and which is made of spring steel, then the plate spring basic member is cooled to predetermined temperature, and then its load is released. After high frequency quenching, shot peening is applied on a face on which high frequency quenching is applied by shots having predetermined average particle diameter.

COPYRIGHT: (C)2006,JPO&NCIPI