An electric field coupling type wireless power feed system including a power transmitting device and a power receiving device which is unlikely to be affected by a noise and which has a reduced size is provided. A capacitive coupling type wireless power feed system includes a power receiving device including a first electrode using an oxide semiconductor film, and a battery and a power transmitting device including a second electrode, wherein the battery is charged by a voltage generated based on an electric field generated between the first electrode and the second electrode. The charging of the battery may be stopped by applying a positive direct-current voltage from a charge control circuit to the first electrode.