Abstract: A timing device comprises a contact assembly, an acting switch and a centrifugal mechanism rotated by a synchronous motor, and a rotatable resiliently biased timing wheel. The acting switch, upon energization of the motor, is moved axially in a direction parallel to the rotary axis of the timing wheel by the centrifugal mechanism to a first position for rotating the said timing wheel and opening a contact between a movable contact plate and a first fixed contact plate of the contact assembly. The acting switch is maintained in the first position by the timing wheel, and is moved to a second position for maintaining the timing wheel in position and closing a contact between the movable contact plate and a second fixed contact plate of the contact assembly, whereby, upon deenergization of the motor, the switch is moved axially in the reverse direction to its normally inoperative state and said timing wheel is rotated back under the action of its biasing means.