A waterproof structure for an electronic device (60) includes: a case (130) which is disposed in a location in a vehicle (10) distant from a receiving antenna (61), which houses a processing unit (69) that processes location information, and which has a wiring hole (171) through which a wire (62) passes; a cylindrical part (172) which extends in the axial direction of the wire from the case in such a manner as to surround the wiring hole; a seal member (167) which is housed in a compressed state in the cylindrical part, and surrounds the wire; and a cap (160) which is attached to the case in an attachable/detachable manner, has a hole (168) through which the wire passes, and prevents the seal member from moving.