An electromagnetic coupler including a conductor pattern formed in a first conductor layer, a feed pattern connected to a feeding system and a ground pattern separated from the feed pattern. The feed pattern and the ground pattern are formed in a second conductor layer parallel to the first conductor layer. A first linear conductor and a plurality of second linear conductors are formed perpendicularly to the first and the second conductor layers. The first linear conductor connects the conductor pattern and the feed pattern. The plurality of second linear conductors connects the conductor pattern and the ground pattern. In addition, the conductor pattern is symmetrical in shape with respect to the connection point between the conductor pattern and the first linear conductor. The plurality of second linear conductors are symmetrical in position with respect to the first linear conductor in a planar view.