An apparatus for producing hydrogen by microwave includes a microwave heater, a reaction tube comprising a catalyst bed, a cap, an output unit and a microwave control box. A method of producing hydrogen using microwaves has steps of feeding gas and liquid, vaporizing the liquid to from a mixed gas and heating the mixed gas. A liquid and a gas are selected at predetermined ratios to form the mixed gas that reacts on the catalyst bed to from hydrogen. Microwaves allow the apparatus to be ready for production quicker and reduce space required by the apparatus. Heating the liquid and gas using microwaves is fast so has a good energy efficiency.