A high purity phosphoric acid, characterized in that it has an impurity content wherein the content of Sb is 200 ppb or less and the content of a sulfide ion is 200 ppb or less, in terms of a product having a H3PO4 concentration of 85 wt %. The above high purity phosphoric acid is useful as an etching fluid for a semiconductor element having a silicon nitride film, an etching fluid for a liquid crystalline display panel having an alumina film, an etching fluid for metallic aluminum, an etching fluid for alumina for a ceraminc, a material of a phosphate glass for an optical fiber glass, a food additive and the like.