PURPOSE: To provide the structure of a knife for facilitating the production thereof concerning the knife of a type for producing the entire knife by individually preparing the blade of the knife and the core member of a handle and bonding the both by welding.

CONSTITUTION: Concerning the knife with which the end face of a ferrule 3 as the core member of handle of the knife is butted and welded on a flat face 2' of a swell 2 as the root of a blade 1, the swell 2 is welded only near the center of a terminal part 6' of the wide side face of the ferrule 3 and concerning a handle member 5, a recess 7 is formed on the surface facing a welding ball 4. Thus, the stable welding bonding between the swell and ferrule can be provided by an extremely simple method and further since the welding face is covered with the recess of the handle member after welding, any mechanical working of the welding face is not required.