To provide a resin which is good in water solubility, is reduced in the amount of monomer components such as unreacted phenol and formaldehyde, is low in odor, is fast in the curing speed, is little in foaming at the curing, is little in degradation by water and is little in corrosion to metals.

The resol type phenolic resin is formed by allowing phenol, formaldehyde and urea to react as essential components. As the reaction catalyst lithium hydroxide and barium hydroxide are used jointly, and an acid is added to the resin after the reaction, to adjust the pH to 6-8.