Abstract: A method of heat treating metallic workpieces using a continuous-heating, sher-type, or gravity-discharge furnace having at least two treatment chambers through which the workpieces successively pass. The chambers, which are provided with doors, serve to respectively heat treat a plurality of workpieces charges, with individual ones of the charges being cyclically received by the respective chambers, being conveyed through the latter while heat treatment is undertaken, and subsequently being released by the chambers. Charges requiring different treatment and/or duration, especially different case-hardening depths during carburization in a two-stage process, can be simultaneously treated while fully utilizing the capacity of the furnace by irregularly conveying the charges in at least one of the treatment chambers in such a way that the charges are released by the chamber or chambers after varying retention times.