Disclosed is a combination lock, comprising a rotatable knob capable of relative rotation, a panel, a bolt, and a dial assembly. The dial assembly comprises a base having a movement chamber, a dial shaft, multiple sets of bushings and dials, a position resetting mechanism, a positioning member, and a protection frame The rotatable knob can be rotated relative to the panel to a first position, second position, third position, or fourth position, so as to achieve locking, automatic password resetting, automatic dial position resetting, and manual password setting. The combination lock uses one-time temporary passwords, thereby achieving superior security performance.

Disclosed in the present invention is a novel code wheel combination lock, comprising a knob and a face plate that can rotate with respect to each other, a lock tongue, and a code wheel assembly. The code wheel assembly comprises a base having an accommodation cavity, a code wheel shaft, several sets of bushings and code wheels, a reset mechanism, a positioning member, and a protection frame; the base is mounted on the face plate; the code wheel shaft passes through a movement cavity and can axially moves; the bushings are sleeved on the code wheel shaft and can rotate together with the code wheel shaft or with respect to the code wheel shaft; the code wheels are sleeved on the bushings and can rotate together with the bushings or with respect to the bushings; the reset mechanism is used for resetting the code wheels; the positioning member is used for limiting reset of the code wheels; the protection frame is used for changing the matching mode between the code wheels and the bushings; in the rotation of the knob and the face plate with respect to each other, there are a first position, a second position and a third position to respectively implement the functions of locking, automatic code wheel reset, and manual password setting. The present invention has a function of automatically resetting the code wheels after unlocking and before locking, thereby improving the product safety and preventing password exposure.