An ultrasonic treatment tool includes a grip part that is provided at a distal end part and that grips a biological tissue in a subject, an ultrasound oscillator that transmits ultrasonic oscillation to the biological tissue gripped by the grip part, and a stress concentration structure that is provided at the grip part and that protrudes from a grip surface facing the biological tissue, in which the stress concentration structure is a long protrusion disposed along a longitudinal direction of the grip part, and a distal end part from the grip surface in a protruding direction is formed in a continuous sawtooth shape.