The electricity supply device (100) supplies electricity using electromagnetic force and opposes an external electricity reception coil (153a). An electricity supply coil (102a) has a hollow section (102b), and has a spiral shape. A reader (103) has an antenna disposed in the projected space resulting from projecting the hollow section (102b) in the central axial direction of the electricity supply coil (102a) and at a position more separated from the electricity reception coil (153a) than the opposing surface that opposes the electricity reception coil (153a) and is of the electricity supply coil (102a), and ID data transmitted by an RF tag (154) installed proximally to the electricity reception coil (153a) is received and detected by the antenna. An electricity-supply-side control unit (104) determines the presence/absence of an electricity reception coil (153a) on the basis of the ID data detected by the reader (103).