Dehalogenation of (2-haloethyl)benzene using Fe particles was carried out in the electric and magnetic fields in a microwave single mode cavity. Microwave irradiation in a magnetic field enhanced the conversion of (2-haloethyl)benzene compared with heating by a mantle heater and microwave in an electric field, while the ethylbenzene selectivities were comparable. Larger Fe particles generated sparks under microwave irradiation, resulting in the increase of ethylbenzene selectivities. These data suggested the reaction acceleration by a local thermal nonequilibrium in the solid-liquid system by the selective microwave heating of the solid.