PURPOSE: To obtain the title fabric improved in the drillability of the printed wiring boards as a use thereof by treating the original glass fabric with a silyl isocyanate compound to effect declining in the tensile strength of the glass fibers comprising said fabric.

CONSTITUTION: A glass fabric freed from the sizing agent bonded thereto by heat cleaning is immersed in a solution of a silyl isocyanate compound of formula I (R is organic residue; n is 1-3) or a tetraisocyanate compound of formula II (in particular, pref. tetraisocyanate silane acetate) and then dried, thus giving the objective glass fabric for laminates with decreased tensile strength of the glass fibers comprising the fabric. The surface of the present fabric is then treated with a coupling agent such as a silane compound into a base material for laminates. This base material is excellent in drillability, enabling the number of the base materials to be increased in their drilling, also being good in the smoothness of the inner walls of the resulting holes.