A scaling rule of magnetic minor hysteresis loops at low applied fields has been examined in plastically deformed low carbon steel and pure Ni. It was found that a power law between hysteresis loss and remanence of a minor loop holds true over the wide range of magnetization from the very low to intermediate range unlike the well-known Steinmetz law. The power-law exponent was an almost constant value of 1.35 being independent of the types of magnetic materials, the level of plastic deformation, and sample shape. The coefficient of the scaling rule increases with deformation and is in linear proportion to coercivity. This behavior was qualitatively explained on the basis of the Rayleigh law and NE??el theory.