To obtain the subject new compound, capable of manifesting new characteristics and widely applicable to industrial uses.

This curdlan phosphate is polysaccharides in which phosphate groups are bound to the glucose residue of a β-1,3-glucan skeleton through an ester linkage and usually contains preferably 0.1-5% curdlan phosphate, based on the curdlan weight and expressed in terms of phosphorus content. The curdlan phosph is obtained by reacting the curdlan with a phosphorus compound selected from an inorganic phosphoric acid (salt) (e.g. metaphosphoric acid), an organic phosphoric acid (salt) (e.g. salicyl phosphate) and phosphorus oxychloride. For example, the curdlan is mixed with the metaphosphoric acid under aqueous neutral conditions and then dry heated at 100-120°C for ≥20min or the curdlan is reacted with the salicyl phosphate at about 15-55°C temperature for about 24hr (wet reaction). The resultant new compound has a branched basic skeleton and is increased in usefulness such as expectable excellent physiological activities and new uses can be expected.