Provided is an axially-limited guide device applied in a parking mechanism. The parking mechanism includes a parking pawl and a parking shift fork that is axially movable. The guide device includes a parking bracket assembly and a guide block. The guide block is configured to be slidably engaged with an execution member at an end of the parking shift fork to allow for a relative rotation of the parking pawl and a rotary shaft. The parking bracket assembly is configured to axially limit the parking pawl and guide the parking shift fork. The parking bracket assembly includes a limiting portion abutting against the guide block. The limiting portion is configured to limit an axial movement of the guide block when the execution member at the end of the parking shift fork is axially disengaged from the guide block. Also provided are a parking mechanism and an automobile.