A portable terminal charging device adopts a configuration in which a large diameter detection coil (43) arranged between a charging coil (8) and a portable terminal (15) and a detection coil (44) that is arranged inward of the large diameter detection coil (43) and that has a smaller diameter than the large diameter detection coil (43) detect a state of a foreign metal object (50) by finding out a decrease in the magnetic flux of an inward section of the charging coil (8) and conversely finding out an increase in the magnetic flux of an outward section thereof, if the foreign metal object (50) is present between a portable terminal installation unit of a support plate (6) and the portable terminal (15).