In this contact mechanism part, driving protrusion parts (43, 44) disposed on one end of a card (40) that slides engage with the free edge part of a moveable contact piece (60), the moveable contact piece (60) is turned by sliding the card (40), and moveable contact points (56, 57) provided to the moveable contact piece (60) come into and out of contact with fixed contact points (52, 53). In particular, the present invention is provided with a pair of driving protrusion parts (43, 44) which protrudes in the opposite direction from corner parts adjacent to the one end of the card (40), and a pair of elastic returning tongue pieces (67b, 67c) which is cut out of the free edge part of the moveable contact piece (60) and which is arranged so as to be able to come into contact with the driving protrusion parts (43, 44). When the moveable contact points (56, 57) and the fixed contact points (52, 53) come into contact with one another, the distance between one of the driving protrusion parts (43) and one of the elastic returning tongue pieces (67b) becomes shorter than the distance between the other driving protrusion part (44) and the other elastic returning tongue piece (67c).