An operation command transmitting device for an ultrasonic treatment apparatus comprising: a graspable housing; a switch contact (33A, 33B) attached to the housing; a pressure receiving portion pressably provided outside the housing; a bar portion extending from the pressure receiving portion toward the switch contact (33A, 33B) along a central axis, the bar portion being movable relative to the housing along the central axis, the bar portion being configured to tilt relative to the housing from an untilted neutral condition; a switch pressing portion which is provided in an opposite side part of the pressure receiving portion in the bar portion, and which is configured to press the switch contact (33A, 33B) in accordance with each of a movement of the bar portion along the central axis and a tilting motion of the bar portion; and an abutment portion (72A, 72B) provided integrally with the housing or provided to be fixed with respect to the housing, the bar portion being configured to come into abutment with the abutment portion (72A, 72B) when the bar portion is tilted from the untilted neutral condition, characterized by further comprising an axis defining portion (63, 65; 81A, 81B) which is provided integrally with the housing or fixed with respect to the housing, and which defines a supporting axis passing through the bar portion, the bar portion being configured to tilt around the supporting axis, a position of the supporting axis relative to the housing being maintained regardless of the movement of the bar portion along the central axis and the tilting motion of the bar portion; and a coupling portion (75; 82A, 82B) which is provided to the bar portion, and which is coupled to the axis defining portion (63, 65; 81A, 81B) while the bar portion is movable along the central axis of the bar portion and is allowed to be tilted around the supporting axis. a graspable housing; a switch contact (33A, 33B) attached to the housing; a pressure receiving portion pressably provided outside the housing; a bar portion extending from the pressure receiving portion toward the switch contact (33A, 33B) along a central axis, the bar portion being movable relative to the housing along the central axis, the bar portion being configured to tilt relative to the housing from an untilted neutral condition; a switch pressing portion which is provided in an opposite side part of the pressure receiving portion in the bar portion, and which is configured to press the switch contact (33A, 33B) in accordance with each of a movement of the bar portion along the central axis and a tilting motion of the bar portion; and an abutment portion (72A, 72B) provided integrally with the housing or provided to be fixed with respect to the housing, the bar portion being configured to come into abutment with the abutment portion (72A, 72B) when the bar portion is tilted from the untilted neutral condition, characterized by further comprising an axis defining portion (63, 65; 81A, 81B) which is provided integrally with the housing or fixed with respect to the housing, and which defines a supporting axis passing through the bar portion, the bar portion being configured to tilt around the supporting axis, a position of the supporting axis relative to the housing being maintained regardless of the movement of the bar portion along the central axis and the tilting motion of the bar portion; and a coupling portion (75; 82A, 82B) which is provided to the bar portion, and which is coupled to the axis defining portion (63, 65; 81A, 81B) while the bar portion is movable along the central axis of the bar portion and is allowed to be tilted around the supporting axis.