To provide a device for processing a surface by collision by which a surface of a certain portion can be easily processed by the collision without causing any apprehension of losing a shot and any problem of consuming the shot.

The device 1 has a vibration face 7 and at least one projectile 11 which is projected toward a processed portion P by the vibration face, and has a retaining means for retaining each projectile within the device. Each projectile is projected toward the processed portion after it is brought into contact with the vibration face. The tip 11C of the projectile is made to collide against the surface and kinetic energy in the projectile is converted to heat due to friction, and also converted to plastic/elastic deformation energy at the collision.