Abstract: A magnet switch arrangement having a long flow path through which outside air must pass to enter the inner chamber of the switch where its working contacts are located to prevent the accumulation of dust and moisture therein. A coil unit (3) having a bobbin (4) is provided within a switch housing (2), the bobbin having a cylindrical portion (4a) and a pair of end faces (4b,4c) formed at both sides of the cylindrical portion. A solenoid coil (5,6) is wound on the bobbin's cylindrical portion. A coil chamber (D) is formed between the coil unit and the switch housing. A cylindrical non-magnetic sleeve (7) isolates the inside from the outside of the coil chamber. A plunger having a movable contact is movable inside of the sleeve so that the plunger shifts the pinion toward the ring gear when the solenoid coil is energized. A switch cover (16) includes a contact chamber for covering the movable contact. Fixed contacts (17a,17b) are provided on the switch cover for supplying electrical power to be switched.