This application discloses a gate-all-around field effect transistor and a method for manufacturing same. In some implementations the method may include: forming a first fin structure on a substrate, where each first fin structure includes one first laminated structure, where the first laminated structure sequentially includes a sacrificial layer, a support layer, and a channel layer from bottom to top; forming a dummy gate structure across the first fin structure, where the dummy gate structure includes a dummy gate dielectric layer, a dummy gate on the dummy gate dielectric layer, and a first spacer on a side surface of the dummy gate; removing parts of the first fin structure located on two sides of the dummy gate structure, to form a second fin structure; performing first etching on a side surface of the sacrificial layer in the second fin structure, to form a first space; forming a second spacer in the first space; performing second etching on a side surface of the channel layer in the second fin structure, to form a second space; and performing selective epitaxy on the side surface of the channel layer in the second fin structure, to form a source region and a drain region, where along a direction of a channel, compared with a side surface, distal to the sacrificial layer, of the second spacer, the side surface of the channel layer after the second etching is closer to the sacrificial layer.