A locking device (3) for a wearing part (2) detachably attached to a soil-working working element (1) by means of quick-coupling elements (11, 21), wherein a locking element (31) attached to the working element (1) includes an end portion (312) projecting from the working element (1) and being provided with an engagement section (313) arranged to engage with a lock-receiving element (22) arranged on a lee-side face (2a) of the wearing part (2).