The present invention provides a treatment apparatus for an endoscope, an endoscope, and an expandable frame. The treatment apparatus for an endoscope includes: a first electrode, including an electrical treatment part and an operating wire； a second electrode, provided inside the endoscope, and including a first electrically conductive part and a sliding contact part electrically connected to the first electrically conductive part, the first electrically conductive part being configured to contact a human body； and a sheath, provided on a surface thereof with a second electrically conductive part, where the operating wire is configured to be passed through the sheath, the sheath is configured to be passed through the endoscope, and when the sheath is located in a preset position, the sliding contact part contacts and is electrically connected to the second electrically conductive part and the sheath is in sliding fit with the sliding contact part.
