PURPOSE: Glass for bonding ferrite, obtained from SiO2, BaO, BO3, ZrO2, ZnO and K2O in a specific proportion, capable of regulating accurately the magnetic effective void width, and giving magnetic heads without a recess or bubble in the glass part.

CONSTITUTION: Glass for bonding ferrite consisting of 16W24wt% SiO2, 50W56wt% BaO, 22W32wt% B2O3, 0.5W2.5wt% ZrO2, 0.5W1wt% ZnO and 0W1wt% K2O. The corrosion of ferrite is scarcely caused in the interface between the ferrite and the glass. The recess depth in the glass part after final polishing and number of bubbles in the glass surface are few, which are quantities out of question.