PURPOSE: To prevent the deterioration of characteristics of a magnetic head by providing an elastic material which absorbs the injecting pressure of synthetic resin at the side of a magnetic core assembly which is stored into a holder in order to avoid the core breakage and the gap opening due to said injecting pressure.

CONSTITUTION: A core assembly contains a butted gap spacer 3, a coil bobbin 5, a coil 4 and a connection terminal 6. An elastic material 10 made of one or more of natural rubber, urethane rubber, silicone rubber, foaming synthetic resin, etc. is put between cores 2 and 2 of said assembly. Then this assembly is put into a holder 7. The holder contains a tape guide 8 and an attachment foot 9 formed in a body. Then synthetic resin is injected into the holder 7 and hardened. In this case, a sufficient amount of resin is injected so as to avoid the shortage of resin, the generation of nests, etc. The material 10 functions effectively to avoid that the gap space is increased and the cores 2 are broken by said injecting pressure. In this way, the production of a magnetic head having high performance is ensured with high yield.