A microfluidic device having a substrate with an electrically conductive element made using a conductive ink layer underlying a hydrophobic layer. The hydrogen supply unit 1 comprises a reformer 2 for reforming natural gas, a fuel cell 3 for generating electric power by use of the reformed gas from the reformer 2, and a purifier 4 for purifying hydrogen from the exhaust gas discharged from the fuel cell 3. Then, the data transfer unit reports a command relating to the transfer error to the CPU after completion of the execution of the command chain, thereby lessening the number of interruptions for error processing, and attaining enhancement in performance of a system. In this manner, data can be loaded into the integrated circuit in-sync with the same clock signal used to control the integrated circuit even though the data is originally transferred in-sync with another clock signal.