An electronic device and an antenna device are provided that use a coil module which is thinned without losing the characteristics of the coil module and which can be mounted in a narrowed space. A coil module including a loop-shaped antenna coil wounded in a planar shape and a sheet-shaped magnetic sheet which is formed of a magnetic material and which overlaps with at least a part of the antenna coil is included. In the coil module, a part of the antenna coil is overlapped with an internal structure of a housing and the magnetic sheet is provided in a position that does not overlap with the internal structure on an antenna coil surface side that overlaps with the internal structure.