A vertically oscillating working device 2 has a body to be oscillated 23 having an inner space that is formed by a cover member 21 and a vehicle wheel 22, which is a body to be worked, and receives working materials 25 in it and also has oscillating means for vertically oscillating the body to be oscillated 23. The working materials 25 are allowed to collide with the vehicle wheel 22 by the oscillation, and thereby the vehicle wheel 22 is worked. With the working device 2, a casting can be oscillated together with hardening materials, and excellent mechanical properties can be uniformly added to a predetermined portion of the casting by the oscillation without changing the position of the casting.