A surgical treatment apparatus is characterized by including a first unit (21) including a first vibration transmission member (31) and a first holding member (39), a second unit (22) including a second vibration transmission member (61), a second holding member (54), and an elastic member (67) provided between the second vibration transmission member (61) and the second holding member (54), configured to be deformed in accordance with a relative arrangement of the second vibration transmission member (61) and the second holding member (54) with respect to the axial direction to give the second vibration transmission member (61) an elastic force in the axial direction, and an adjustment coupling mechanism (69, 74) to couple the first unit (21) and the second unit (22) with each other, arrange the first vibration transmission member (31) and the second vibration transmission member (61) coaxially to abut the end portion of the first vibration transmission member (31) and the end portion of the second vibration transmission member (61) against each other, and adjust a relative arrangement of the first holding member (39) and the second holding member (54) with respect to the coaxial direction to be constant to adjust a deformation amount of the elastic member (67) to be constant.
