A surgical fastener including a filament formed into a generally helical shape around a fastener axis and having a plurality of coils. At least one first sensor and one second sensor are connected to one another in a cascade in such a manner that the sensor signal from the first sensor is converted into a first control current which is applied as a bias current to the second sensor, the two angular dependencies of the first and second sensors being multiplied. Defective filling of the buried conductor and the cracking of the inter-layer insulating film can be prevented. The method may then involve attempting to acquire service from a second communication system that is more desirable than the first communication system. For this purpose, a surface treatment apparatus incorporating a sheet heating unit which heats a sheet having at least a thermoplastic resin layer, and a sheet depression and protrusion-forming unit disposed on the downstream process side of the sheet heating unit which forms depressions and protrusions on the thermoplastic resin layer, is provided.