Repetitive-pulse generation of the diode-pumped Er:YAG laser (λ = 2.94 µm) in the free mode and in the mode of cavity passive Q-switching was achieved using a Q-switch based on the Fe2+:ZnSe crystal. When using pump pulses 3 ms long, the pulse-average output power of the Er:YAG laser in the free generation mode was 0.5W. In the passive Q-switching mode, giant pulses 180 ns long with an energy of 3 µJ were obtained.