A small-size switch having an arc runner is provided. The switch includes fixed contacts each of which is bonded with each one end of fixed contactors 6U; movable contacts 10U each of which is bonded with each of movable contactors 9 and each of which can contact with or leave from each of the fixed contacts; an interphase barrier 80 that is disposed so as to partition the movable contacts 10U one by one and that is an insulator; and an arc runner that has an arc extinguish portion 12A and that is disposed so as not to intrude in a space where the interphase barrier 80 and the movable contactor 9 are most closely located.