An ink jet recording paper capable of compatible with high speed ink jet printers is provided. By using, as a fiber material, mercerized pulp obtained by applying an alkali treatment to pulp, an ink jet recording paper of high ink absorption speed and high ink coloring density is formed. Since the paper itself has excellent ink absorption speed, there is no requirement for applying coating for improving the ink absorption and it can be used as non-coated type ink jet recording paper.