Quick changer for coupling and uncoupling attachments to and from a dipper arm of an earth-moving machine, wherein the quick changer has a quick-changer frame which is preferably in the form of a housing and has on its front side two laterally mutually spaced claw-shaped catch hooks with a forwardly facing opening for engaging on a shaft (9a, 9b, 9c) on the attachment and on the rear side of which, i.e. on an outer side opposite the openings of the catch hooks, two locking bolts (38a, 38b; 50a, 50b) which are arranged next to one another are accommodated in a retractable and extendable manner, and wherein the quick-changer frame comprises a first single-acting or double-acting hydraulic linear actuator system (18a, 40a, 45a, 18b, 40b, 45b; 48a, 45a, 48b, 45b), via which the locking bolts (38a, 38b; 50a, 50b) can be moved linearly via hydraulic pressure between a locked position and an unlocked position for locking and unlocking on the attachment, wherein the locked position is displaced rearwardly relative to the unlocked position and the unlocked position is displaced forwardly relative to the locked position, and wherein a securing device is provided in order to prevent, in the event of insufficient locking of the locking bolts (38a, 38b; 50a, 50b), a drop of the attachment from the quick changer, and a separate, hydraulically driven actuating device (19, 33, 34, 46; 69; 79, 73; 83) for actuating the securing device, characterized in that the securing device comprises at least one securing claw (30; 60; 70; 80) which is suitable for gripping the shaft (9a, 9b, 9c) and which is pivotably arranged on the front side of the quick-changer frame about an axle parallel to the axis of the shaft (9a, 9b, 9c), wherein the securing claw (30; 60; 70; 80) is pivotable via the actuating device (19, 33, 34, 46; 69; 79, 73; 83) at least from its release position in which it lets go of the shaft (9a, 9b, 9c) into its engagement position in which it grips the shaft (9a, 9b, 9c). the quick changer has a quick-changer frame which is preferably in the form of a housing and has on its front side two laterally mutually spaced claw-shaped catch hooks with a forwardly facing opening for engaging on a shaft (9a, 9b, 9c) on the attachment and on the rear side of which, i.e. on an outer side opposite the openings of the catch hooks, two locking bolts (38a, 38b; 50a, 50b) which are arranged next to one another are accommodated in a retractable and extendable manner, and wherein the quick-changer frame comprises a first single-acting or double-acting hydraulic linear actuator system (18a, 40a, 45a, 18b, 40b, 45b; 48a, 45a, 48b, 45b), via which the locking bolts (38a, 38b; 50a, 50b) can be moved linearly via hydraulic pressure between a locked position and an unlocked position for locking and unlocking on the attachment, wherein the locked position is displaced rearwardly relative to the unlocked position and the unlocked position is displaced forwardly relative to the locked position, and wherein a securing device is provided in order to prevent, in the event of insufficient locking of the locking bolts (38a, 38b; 50a, 50b), a drop of the attachment from the quick changer, and a separate, hydraulically driven actuating device (19, 33, 34, 46; 69; 79, 73; 83) for actuating the securing device, characterized in that the securing device comprises at least one securing claw (30; 60; 70; 80) which is suitable for gripping the shaft (9a, 9b, 9c) and which is pivotably arranged on the front side of the quick-changer frame about an axle parallel to the axis of the shaft (9a, 9b, 9c), wherein the securing claw (30; 60; 70; 80) is pivotable via the actuating device (19, 33, 34, 46; 69; 79, 73; 83) at least from its release position in which it lets go of the shaft (9a, 9b, 9c) into its engagement position in which it grips the shaft (9a, 9b, 9c).