Abstract: Disclosed is a self-locking apparatus for a linear actuator, which relates to the field of linear actuation equipment. The self-locking apparatus includes a one-way bearing and a friction collar, wherein the one-way bearing includes an inner race and an outer race, the inner race being sleeved to the rotary screw of the linear actuator, the friction collar being connected to the outer race; wherein the self-locking apparatus further includes a friction member fitted with the friction collar, such that when the rotary screw rotates forwardly, the outer race does not rotate; and when the rotary screw rotates reversely, the outer race, the inner race, and the friction collar rotate synchronously, such that friction is produced by contacting between the friction collar and the friction member. Further disclosed is a linear actuator applying the self-locking apparatus.