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 (B) 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 (B) 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 (B) 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 (B) 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 (B) 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 (B) 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. <EOS>