A device for returning a reciprocating mechanism to a predetermined intermediate position of reciprocating motion, comprises a reciprocating link movable in accordance with a predetermined reciprocating motion, a pair of positioning members provided at both sides of the predetermined intermediate position of reciprocating motion, a pair of movable blocks, and a single resilient member interconnecting the movable blocks. The positioning members is adapted to position the movable blocks by abutting the movable blocks against the respective positioning members via a biasing force created by the single resilient member. The movable blocks is adapted to return the reciprocating link to its predetermined intermediate position by abutment of the reciprocating link on both the movable blocks, for restricting a reciprocating motion of the reciprocating link via the biasing force created by the single resilient member. During the reciprocating motion, one of the movable blocks breaks contact with the associated positioning member and additionally the reciprocating link breaks contact with the other positioning member by pushing the associated one of the movable blocks in a direction of increasing the biasing force created by the single resilient member.