Disclosed is an ultrasonic knife head (100), wherein a centre pole (1) of the ultrasonic knife head (100) can rotate around an axis and thread-connect to a driving handle (200), a power transmission device is fixedly connected to the centre pole (1), and the power transmission device has at least one bearing surface (41)； the rotating device comprises a crowding mechanism and a rotation driving mechanism, wherein the rotation driving mechanism has at least one force applying surface (51), one bearing surface (41), wherein the force applying surface (51) is a surface which is not perpendicular to the axis, and the surfaces are capable of engaging with each other, and the crowding mechanism provides a thrust pressure to press the rotation driving mechanism against the power transmission device, thereby engaging the force applying surface (51) with the bearing surface (41), and the thrust pressure is set to be the thrust pressure the rotation driving mechanism can overcome when the interaction force between the force applying surface (51) and the bearing surface (41) is greater than the predetermined value, disengaging the force applying surface (51) and the bearing surface (41). As long as the thrust pressure is set reasonably, the set torque can be delivered, and when the torque is greater than the set value, the rotation driving mechanism will overcome the thrust pressure and slip, thereby limiting the delivery of the torque and providing protection. The present invention also provides an ultrasonic knife comprising the ultrasonic knife cutting head (100).L'invention concerne une tête de couteau à ultrasons (100), où un pôle central (1) de la tête de couteau à ultrasons (100) peut tourner autour d'un axe et être connecté par un fil à une poignée de conduite (200), un dispositif de transmission de puissance est connecté de manière fixe au pôle central (1), et le dispositif de transmission de puissance a au moins une surface d'appui (41)； le dispositif rotatif compren
