The present invention discloses a starter for starting an internal combustion engine which comprises:(a) a starter motor having a starter shaft;(b) a pinion gear splined to the starter shaft so as to be slidable along the starter shaft for connection and disconnection of the starter motor to the engine;(c) a shifting motor having a shifting shaft;(d) a sliding means helical splined to the shifting shaft for a reciprocal movement along the shifting shaft according to a rotational movement of the shifting shaft; and(e) a shift arm for transmitting the reciprocal movement of the sliding means to the pinion gear so as to move the latter for connection and disconnection of the starter motor and the engine.