The present invention provides a high purity heparin useful to be a pharmaceutical product, cosmetics, research reagent, or the like, and a method for producing the same, more specifically, a heparin which does not substantially contain a nitrous acid degradation-resistant impurity and a method for producing a heparin, comprising mixing an aqueous solution of 5 to 30% by weight of the heparin with ethanol having an amount (volume) 0.2 to 1 times the amount (volume) of the aqueous heparin solution to obtain a colloidal precipitate of heparin.
