To provide a mobile communication service utilizing magnetic waves which are propagated under water or under seawater with a relatively low loss.

Magnetic waves are efficiently transmitted and received under water or under seawater by a loop antenna 222 connected to a transceiver 221 installed in a base station 22 fixed on land. Whereas, magnetic waves are efficiently exchanged with the base station 22 or with a marker 31 provided separately by a loop antenna 212 connected to a transceiver 211 installed in a mobile station 21 moving on the sea. Thus, communications can be performed between the fixed station 22 and the mobile station 21 or between the mobile station 21 and the marker 31.