A surgical apparatus, comprising: an adapter, comprising: a casing, comprising an opening provided at a distal end of the casing; and a rotary head, sleeved onto the opening of the casing and configured to be rotatable relative to the casing, the rotary head comprising a first through hole and a first guide member disposed in the first through hole; a shaft assembly, detachably connected to the adapter and comprising: a firing sleeve; and a coupling component, disposed at an end of the firing sleeve, the coupling component being configured to insert into the opening of the casing after passing through the first through hole of the rotary head, the coupling component comprising a coupling casing and a second guide member disposed on the coupling casing, characterized in that the first guide member comprises a first wedge portion tapered in a first direction (+A) parallel to a central axis of the rotary head, and the second guide member comprises a second wedge portion tapered in a second direction (-A) parallel to the central axis of the rotary head, the first direction (+A) is opposite to the second direction (-A), and the first guide member and the second guide member are engaged with each other in a snap-fit manner to maintain both the rotary head and the shaft assembly in a locked position. an adapter, comprising: a casing, comprising an opening provided at a distal end of the casing; and a rotary head, sleeved onto the opening of the casing and configured to be rotatable relative to the casing, the rotary head comprising a first through hole and a first guide member disposed in the first through hole; a casing, comprising an opening provided at a distal end of the casing; and a rotary head, sleeved onto the opening of the casing and configured to be rotatable relative to the casing, the rotary head comprising a first through hole and a first guide member disposed in the first through hole; a shaft assembly, detachably connected to the adapter and comprising: a firing sleeve; and a coupling component, disposed at an end of the firing sleeve, the coupling component being configured to insert into the opening of the casing after passing through the first through hole of the rotary head, the coupling component comprising a coupling casing and a second guide member disposed on the coupling casing, characterized in that the first guide member comprises a first wedge portion tapered in a first direction (+A) parallel to a central axis of the rotary head, and the second guide member comprises a second wedge portion tapered in a second direction (-A) parallel to the central axis of the rotary head, the first direction (+A) is opposite to the second direction (-A), and the first guide member and the second guide member are engaged with each other in a snap-fit manner to maintain both the rotary head and the shaft assembly in a locked position. a firing sleeve; and a coupling component, disposed at an end of the firing sleeve, the coupling component being configured to insert into the opening of the casing after passing through the first through hole of the rotary head, the coupling component comprising a coupling casing and a second guide member disposed on the coupling casing, characterized in that the first guide member comprises a first wedge portion tapered in a first direction (+A) parallel to a central axis of the rotary head, and the second guide member comprises a second wedge portion tapered in a second direction (-A) parallel to the central axis of the rotary head, the first direction (+A) is opposite to the second direction (-A), and the first guide member and the second guide member are engaged with each other in a snap-fit manner to maintain both the rotary head and the shaft assembly in a locked position.