A handle for a treatment device includes: a handle main body held by an operator； a first operation input body which is provided on the handle main body and which is rotatable in the first and second directions relative to the handle main body； an interlock body which is provided rotatably in third and fourth directions relative to the first operation input body, the interlock body being configured to actuate in accordance with an input of an operation to the first operation input body, and to rotate in an appropriate direction of the third direction and the fourth direction when the first operation input body is rotated in the first direction and the interlock body being configured to engage with the handle main body to restrict rotation of the first operation input body in the second direction； and a second operation input body rotatable in fifth and sixth directions relative to the handle main body, the second operation input body being configured to receive an input of an operation to disengage the interlock body from the handle main body when the second operation input body is rotated in the fifth direction.
