An ultrasonic surgery device (100), comprising a tool tip (10) and a first holding arm (20) provided at a distal end of the ultrasonic surgery device (100). The tool tip (10) comprises a top surface (11), a bottom surface (12), and first and second side surfaces (13, 14). The top surface (11) comprises a first engagement surface (111) and a second engagement surface (112) connected together, forming a first edge (113) therebetween. The first engagement surface (111) is connected to the second side surface (14), the second engagement surface (112) is connected to the first side surface (13). The bottom surface (12) comprises a third engagement surface (121) and a fourth engagement surface (122) connected together, forming a second edge (123) therebetween. The third engagement surface (121) is further connected to the second side surface (14), and the fourth engagement surface is connected to the first side surface (13). The first and fourth engagement surfaces (111, 122) respectively form first and second angles (α, β) between tangent lines at the first and second edges (113, 123) and the first and third engagement surfaces (111, 121). The first angle (α) and the second angle (β) are different. The tool tip (10) and the first holding arm (20) are rotatable relative to each other, such that the first holding arm (20) can engage with and release from the top portion (11) or the bottom portion (12) so as to perform a process on tissue.Linvention concerne un dispositif de chirurgie à ultrasons (100), comprenant une pointe doutil (10) et un premier bras de maintien (20) prévu sur une extrémité distale du dispositif de chirurgie à ultrasons (100). La pointe doutil (10) comprend une surface supérieure (11), une surface inférieure (12), et des première et seconde surfaces latérales (13, 14). La surface supérieure (11) comprend une première surface de mis en prise (111) et une deuxième surface de mise en prise (112) reliées lune à lautre, formant un premier bord (113) entre e
