Prepreg and printed wiring board for a printed wiring board

The present invention, long-term connection substrates useful stability excellent printed circuit board and, and to provide a prepreg that can form such a substrate. The prepreg of the present invention, a polybenzazole fiber, a printed wiring prepreg substrate containing a curable resin composition, wherein the polybenzazole fiber cracking rate of 10 pieces / 1000 m or less, an elastic modulus higher 200GPa 350GPa or less, and the linear expansion coefficient of the fiber axis direction (100 ° C. or higher 200 ° C. or less) is equal to or less than -3 ppm / ° C. or higher -20 ppm / ° C..