Precipitation hardening by simulated complete firing and holding condition in a silver-free metal-ceramic alloy of Pd-Cu-In-Ga system was investigated by means of hardness test, field emission scanning electron microscopic observations, X-ray diffraction analysis and energy dispersive X-ray spectrometer analysis. Most effective condition for hardening of alloy was obtained at cooling rate of stage 1 (firing chamber opens about 70 mm) and starting temperature of 600℃. After simulated degassing treatment, the hardness value of solution treated specimen decreased by about 20 Hv, and during the simulated complete firing cycle, such a low hardness value was maintained. By holding the specimen at 600℃ and 700℃ after simulated complete firing, the hardness increased apparently. However, the decrease in hardness by overaging occurred within 30 min at the holding temperature of 700℃. The age-hardening of a silver-free Pd-Cu-In-Ga alloy resulted from precipitation of the CuPd phase containing Ga and In from the Pd-rich matrix.