An object of the present invention is to provide a technique related to the production of a red colorant composition derived from iridoid compounds, and more particularly, a technique for producing an acid-resistant red colorant composition derived from iridoid compounds that is preferable from the viewpoint of safety of the colorant composition produced and its manufacturing cost. The present invention provides a method for producing a red colorant composition derived from iridoid compounds, including a step of performing red color development that involves reaction of iridoid aglycones having a carboxyl group at position 4 of an iridoid skeleton with amino group-containing compounds, said red color development being performed in a solution in which ascorbic acid, similar compounds thereof, or two or more compounds selected from the group consisting of said ascorbic acid and said similar compounds are contained at a molar ratio of 5 or more with respect to all iridoid compounds in the solution, whereby red colorant compounds having acid resistance are generated.