In a trigger switch having a normal and reverse switching lever configured to switch the direction of rotation of a motor, a case is formed with a speed control unit storage chamber for storing a speed control unit, a revolving shaft storage chamber for storing a revolving shaft of the switching lever and a contact strip member storage chamber with continuing from the revolving shaft storage chamber through a shielding member therebetween for storing contact strip member of the switching lever, the revolving shaft storage chamber is formed with a revolving shaft engaging hole configured to allow the revolving shaft to be inserted in an engaged state on an upper portion thereof on the side of the trigger lever, and a waterproof device for covering at least a gap between the switching lever and the revolving shaft engaging hole is provided to prevent entry of water therein.