A high-frequency treatment apparatus is characterized by comprising an insertion portion (21), a covering portion (24) provided in a distal end portion of the insertion portion (21), an electrode portion (26) provided in the covering portion (24), through which high-frequency current is to flow, including a side treatment portion (38a) arranged along an outer surface of the covering portion (24) and a distal end treatment portion (38b) formed of a distal end portion of the electrode portion (26), and configured to be moved between a forward position where the distal end treatment portion (38b) is protruded from the covering portion (24) with respect to a forward and backward movement direction and a backward position where the distal end treatment portion (38b) is arranged within the covering portion (24) with respect to the forward and backward movement direction, and an operation member (27) inserted through the insertion portion (21) and connected to the electrode portion (26) wherein the electrode portion (26) is configured to be moved by operating the operation member (27).
