Frequency distribution of the maximum amplitude of seismograms at a station exhibits a power‐law relation, which is the Ishimoto–Iida law (II law). We investigate whether the II law is applicable to modern strong‐motion seismograms. Distribution of maximum amplitudes records at stations of The Committee of Earthquake Observation and Research in the Kansai Area (CEORKA) network, western Japan, exhibits properties of the power law or the II law. The observation matches well with the prediction, which is based on existing ground‐motion prediction equations for Japan. Parameters of the observed II law could be used in understanding the probabilities of future seismic hazard intuitively.