In a magneto-resistive effect type head having provided between a lower shield layer and an upper shield layer an MR sensor with a magneto-resistive effect or a gigantic magneto-resistive effect; electrode layers electrically connected to the MR sensor; and lower and upper insulating layers mangetically and electrically isolating the MR sensor and the electrode layer from the shield layers, when the gap length is reduced and the lower and upper insulating layers are decreased in thickness, the insulating layers are more liable to a dielectric breakdown by static electricity produced in the manufacturing process of the magnetic head. In a magneto-resistive effect head, the portion of the insulating layer in which the MR sensor 30 and the lower or upper shield layer 10 or 60 do not face each other (in other words, the second lower insulating layer 22 or the second upper insulating layer 52) is formed by a lower-resistivity insulating film than the other portion of the insulating layer in which the MR sensor and the layers 10 or 60 face each other (in other words, the first lower insulating layer 21 or the first upper insulating layer 51). If electric charge accumulates in the electrode layer or shield layer by static electricity, a minute current flows through the low-resistivity insulating film, reducing a potential difference between the electrode layer and the shield layer and therefore the insulating layers can be prevented from breaking by static electricity.