The treatment tool (1) has a housing (3). An end effector (5) is provided at the tip of the shaft (2) attached to the housing (3). The operator holds the grip (22) of the housing (3) between the palm (H1) and thumb (F1) of the right hand (H0) and handles the middle finger (F3), ring finger (F4), and little finger (F5). Hook on (27). The grip pieces (12, 13) of the end effector (5) can be opened and closed by moving the handle (27). The fingertip of the index finger (F2) is brought into contact with a raised portion (45A) formed on the first outer surface (31A) of the housing (3). By doing so, it is possible to prevent the first side button (41A) attached to the first outer surface (31A) from being erroneously pressed with the index finger (F2). When the second side button (41B) attached to the second outer surface (31B) of the housing (3) is pressed with the thumb (F1), the treatment instrument (1) is operated in the first operation mode. When the front button (43) attached to the outer front surface (33) of the housing (3) is pushed with the index finger (F2), the treatment instrument (1) is operated in the second operation mode.
