To provide a printing plate material being excellent in plate wear resistance and also free of a stain of a non-image part and having excellent printing suitability and excellent properties of on-machine development, and a developing method thereof.

In the printing plate material having on an aluminum base one or more image forming layers containing hot-melt particles, the respective angles of contact of water and diiodomethane with the surface of aluminum located on the image forming layer side of the base and not coated with the image forming layer are 50 degrees or less.