The absolute requirement for steel material can be hardened directly is the carbon content of this material is more than or equals to 0.3 %. This steel material is recognized as medium carbon steel and above. Carburizing process is an effort to increase low carbon content in soft steel material which have less than 0.3 % it can be done by adding carbon content up to 0.3 % and above. The tool commonly used for this process called pack carburizing device and the process occur in furnace atmospheric pressure. In this research, carbon content adding process held on pressurized pack carburizing container, and the pressure was given mechanically from two axial direction named biaxial pressing carburizing process. The speciment material used in this research is local low carbon steel (ST.37) and coconut shell active charcoal powder. Process parameter The process parameter are pressure, temperature, and hoding time. The best result is achieving at a process temperature of 1000 ºC with 3 hour holding time and biaxial pressure of 2 MPa with 115.4 HRB, 823,6 N/mm2, and 0,41 % the incensement of carbon content from 0,27 % to 0,40 %.