A miniature pneumatic device includes a miniature fluid control device and a miniature valve device. The miniature fluid control device includes a gas inlet plate, a resonance plate, a piezoelectric actuator and a gas collecting plate. A first chamber is formed between the resonance plate and the piezoelectric actuator. After a gas is fed into the gas inlet plate, the gas is transferred to the first chamber through the resonance plate and then transferred downwardly. Consequently, a pressure gradient is generated to continuously push the gas. The miniature valve device includes a valve plate and a gas outlet plate. After the gas is transferred from the miniature fluid control device to the miniature valve device, the valve opening of the valve plate is correspondingly opened or closed and the gas is transferred in one direction. Consequently, a pressure-collecting operation or a pressure-releasing operation is selectively performed.