PROBLEM TO BE SOLVED: To easily and accurately product a multi needle type injection needle assembly in which all needle tubes are projected from a needle hub surface by an equal distance.SOLUTION: A multi needle type injection needle assembly is produced using twice insert molding. In a first insert molding, a first insert molding 10 comprising a relatively simplified structure formed of a needle tube 12 and a body part 11, is produced. Therefore, it is possible to maintain an accurately constant projection amount of each needle tip in plural insert moldings 10. Then, a second insert molding is performed using the plural first insert moldings 10, so that, a surface to which the needle tips of the respective first insert moldings 10 project, becomes substantially flush. By dividing the insert molding step to two steps, it is possible to maintain the accurately constant projection amount of each needle tip in a multi type injection needle assembly comprising a complicated structure, so that, occurrence of defective units and waste loss can be reduced.SELECTED DRAWING: Figure 1
