A metal soap, comprising metal soap particles in which a fatty acid has from 6 to 22 carbons, and an inorganic crystal nucleating agent with an average particle size of 0.01 to 20 µm absorbed internally into the metal soap particles, wherein the cumulative diameter at 50% of the metal soap particles on a volumetric basis is 1.0 to 30.0 µm, and the internal absorption rate A, represented by formula (1) below, is 30% or greater. Internal absorption rate A=100−X/X×100 X amount of inorganic crystal nucleating agent contained within metal soapX amount of inorganic crystal nucleating agent contained within pulverized metal soap passed through a 325-mesh filter (wherein X and X are average values obtained by elemental analysis at three locations in an area of 15 µm square, using a scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX), under conditions of an accelerating voltage of 10 kV and a height of 15 mm)
