An electrocautery instrument for endoscopic therapy includes an operation handle and a rotatable positioning means. The operation handle includes a cylindrical member, a fastening element, and a fixing protruding element. The fastening element and the fixing protruding element are disposed on the cylindrical member which further has a first inner hole. The rotatable positioning means encloses the cylindrical member and includes a rotatable element, a second inner hole, a clasping member, and securing units. The clasping member is disposed on a side wall of the second inner hole and engages with the fastening element. The rotatable element is provided for rotating the rotatable positioning means, so that the fixing protruding element can be positioned on any corresponding securing unit. Therefore, an electrocautery rod can be connectedly moved with the operation handle, thereby reducing components of the electrocautery instrument, and thus the cost is reduced greatly.
