A power shutoff device includes: a fuse to shut off conduction between the input portion connected to a power source side and the output portion connected to a load side; a box having a first face side with the input portion, the output portion, and the fuse to be assembled thereon; and a lock portion to fix one of the input portion and the output portion to the box. The one of the input portion and the output portion is integrally provided to the fuse. The other of the input portion and the output portion includes a first terminal portion integrally provided to the fuse and fixed to the box via a bolt, and a second terminal portion separately provided from the fuse and connected to the first terminal portion via a connecting member being attachable and detachable on a second face side of the box.