A portable terminal charging device includes a large diameter detection coil arranged between a charging coil and a portable terminal, and a further detection coil arranged inward of the large diameter detection coil and having a smaller diameter than the large diameter detection coil. The large diameter detection coil and the further detection coil detect a state of a foreign metal object by finding out a decrease in the magnetic flux of an inward section of the charging coil and conversely finding out an increase in the magnetic flux of an outward section thereof, if the foreign metal object is present between a portable terminal installation unit of a support plate and the portable terminal.