Abstract: The invention concerns a treatment machine for low pressure carburizing of metal parts comprising at least one carburizing temperature-setting cell (2), one carbon-enriching cell (3) and one carbon-diffusing cell (4), arranged in succession one after the other. The cells (2, 3, 4) are of standard shape and of length (L1, L2, L3) adaptable and proportional to the duration of the treatment performed in each cell. Each cell (2, 3, 4) comprises a treatment zone (14) located between an input module (10a) and an output module (10b), each constituting a cold zone, thermally insulated from the treatment zone (14) of the corresponding cell (2, 3, 4). The machine (1) comprises means for driving forward and transferring parts between the cells, located in the input (10a) and output (10b) modules of the cells (2, 3, 4).