Abstract: The invention relates to a method and a device for causing a first body (3, 7, 14), which is held in engagement with a second body (1, 8, 12), to move along said body, said second body comprising material which may be caused to undergo a dimensional change across the intended direction of movement due to magnetostrictive, electrostrictive or piezoelectrical action. Said first body (3, 7, 14) is continuously held in cooperation through form engagement with a zone (2, 10A, 10B, 15) on said second body, which is caused to undergo a dimensional change across the intended direction of movement under the influence of a magnetic field or an electrical field said zone (2, 10A, 10B, 15) by displacement of said magnetic or electric field in the intended direction of movement being displaced in said direction during simultaneous driving action on said first body (3, 7, 14) through form engagement for coupled movement together with said zone (2, 10A, 10B, 15).