This paper is concerned with portable pneumatic power source using chemical reaction of sodium bicarbonate and citric acid. Carbon dioxide generated in the chemical reaction is used as the compressed air. Both sodium bicarbonate and citric acid are inexpensive, nontoxic, and readily available. This paper is organized as follows. Firstly, the characteristics of the chemical reaction is surveyed and the appropriate pneumatic power source system is discussed. Secondly, a pressure booster that can achieve a stable air generation system without external power is described. Thirdly, the experiment using the prototype system is conducted to confirm the effectiveness of the proposed method.