PURPOSE: To provide an injection mold core for producing a slender uniform- walled and bottomed tubular container and the manufacturing method of an injection-molded body by a method wherein uniform influx of resin into the cavity of a mold is made possible at a low cost without developing the deformed shape of a molded article and its whitening.

CONSTITUTION: The manufacturing method of an injection-molded article concerned is performed by employing an injection mold core 7, which has a round bar 6 with its outer surface shape corresponding to the inner wall shape of a slender and bottomed tubular container to be molded and near the tip of the round bar 6 of which a plurality of grooves 8 having nearly the same shape as each other are formed axially symmetrically about the axis of the round bar 6 or one groove 8 is spirally formed.