A high pressure injection nozzle member is formed of a super hard alloy or a hard material of carbide series mainly composing of a tungsten carbide as, wherein the tungsten carbon is composed of grains each having a diameter of less than 1 .mu.m. At least one kind of carbide or solid solution of carbide selected from Ti, Ta, V, Cr, Mo, Hf, or Zr by a weight % of less than 10.0% is added. A binding material essentially consisting of at least one of iron group elements by weight % of 0.2 to 2.0% may be further added. The super hard alloy or a hard sintered material has a high abrasion proof property and has a hardness more than about HRA 94.0. Nitride or nitride solid solution may be utilized in place of carbide or carbide solid solution. The nozzle member is particularly suitable for an abrasive water jet.