The printing head module includes a bracket, a plurality of cartridges, a first piston, a pivot shaft, and a control unit. The bracket includes a plurality of through holes. The cartridges coaxially aligned with each other, each of the cartridges includes a leaning portion and contains the modeling material and a nozzle for extruding the modeling material. The leaning portion is leaning against the bracket when the cartridge is located at the printing position. The first piston is configured to slide along an extensional axis of the cartridge and drive the cartridge to move toward the printing position. The pivot shaft is connected to the bracket and adapted to rotate the cartridge to a working location. The control unit is coupled to the pivot shaft and the first piston for controlling the first piston and the rotation of the bracket.