To provide a surface treatment device, capable of restricting power consumption, improving the intensity of a generated magnetic field, and improving work efficiency of surface treatment.
This surface treatment device 1 is provided with a storage tank 9, an electromagnetic coil 8, and a magnetic member 78. The storage tank 9 is formed cylindrical to store both magnetic abrasive grains and a subject item 2 to be treated. The electromagnetic coil 8 is formed cylindrical to position the storage tank 9 inside it. The electromagnetic coil 8 generates a rotating magnetic field inside the storage tank 9 to make the magnetic abrasive grains to rotate and revolve to collide with the outer surface of the subject item 2. The magnetic member 78 is provided between the inner circumferential surface of the electromagnetic coil 8 and the outer circumferential surface of the storage tank 9, and installed on the inner circumferential surface of the electromagnetic coil 8.