Electronic apparatus system, and operation control method

An electronic apparatus system of this invention includes an electronic apparatus (1), and a fuel cell unit (2) which is detachable from the electronic apparatus (1). The fuel cell unit (2) incorporates a DMFC (22) that can produce electricity by chemical reaction, and a rechargeable secondary battery (23). The fuel cell unit (2) has a function of informing the electronic apparatus of the states of the DMFC (22) and secondary battery (22) incorporated in it as state information. The electronic apparatus (1) has a function of executing its operation control on the basis of the state information sent from the fuel cell unit (2).