The invention provides a method for efficiently improving emulsifying ability of gum arabic, in other words, a method for producing gum arabic with excellent emulsifying ability. Further, the present invention provides a method by which a gum arabic modified so as to have a high emulsifying ability can be obtained without involving the problem of forming syrupy masses or sticking to the vessel or the trouble of excessive dehydration or charring. The above-described methods can be carried out by heating gum arabic (unmodified) under dry conditions. Preferably, the method is carried out by heating gum arabic in such a manner that the loss-on-drying is not more than 3%.