To provide an apparatus for facilitating instantaneous killing of a live fish with a knife and removal of blood, and removal nerve from the fish for improving and maintaining the freshness and quality of fish meat.

A live fish to be processed is inserted into the treating apparatus, in a manner of placing the side to be thrust with a knife along a fish sliding and bending plate. A fish pressing plate is closed by the own weight of the live fish; the apparatus is adjusted to the size of the fish at first with a fish-size adjuster; the neck of the fish is bent; the whole fish body is pressed and fixed in a upside-down state; the neck spinal cord, the gill, and the like, are thrust with a knife cutter driven with a cylinder pressure or a manually driven knife cutter, and at the same time, the tail spinal cord is cut with a tail-cutting knife; the neural arch and the blood vessel arch in the spinal cord are thrust with a steel rod or an air nozzle; and the blood and the nerve are pushed and pulled out by applying pressure to the spinal cord.