This article is a faithful translation of Max Planck's original publicationfrom 1901: "Ueber das Gesetz der Energieverteilung im Normalspectrum; vonMax Planck," where he justifies his law that he had found empirically a fewmonths earlier.No translation found on the Internet respects the original form. We offerthis translated version for students or amateurs wishing to understand ordiscover the origins of Planck's law and Quantum physics.