A magnetic device includes a sheet-type coil including a planar conductive coil and an insulating substance; and a sheet-type first magnetic member disposed on at least one of upper and lower surfaces of the sheet-type coil, where a magnetic permeability of the insulating substance is smaller than a magnetic permeability of the first magnetic member. The magnetic device preferably includes a second magnetic member provided at a predetermined area of the sheet-type coil, the second magnetic member being made of a resin containing a magnetic powder and having a permeability larger than the insulating substance and smaller than the first magnetic member. The predetermined area is at least one position selected from a center portion and a peripheral portion of the sheet-type coil where a conductor constituting the planar conductive coil is not present. Further, a power supply module of the present invention includes this magnetic device according to the present invention.