A medical treatment method comprises orally inserting a first endoscope having
a first treatment tool provided thereto into a body cavity, inserting a first insertion
member insertion support tool from at least one of abdominal and transdermal cavities
into the body cavity, inserting a second endoscope having a second treatment tool
provided thereto into the body cavity through the first insertion member insertion
support tool, grasping a lesioned part by the second treatment tool inserted into
the body cavity by the second endoscope, cutting the lesioned part by the first
treatment tool inserted into the body cavity by the first endoscope, and collecting
the lesioned part.