Abstract: It is provided a polyester cyclic compound represented by formula (1). It is also provided a complex of a polyester cyclic compound represented by formula (1), (3) or (4) and a compound containing an OH group(s). It is still further provided a bonded body of an ester compound and the cyclic compound represented by the formula (1), (3) or (4), or the complex. The above-described compounds demonstrate various pharmacological effects, such as carcinostatic effect and immunological regulation, specifically to a living body. (In the formulae, each "R" is independently H, a C.sub.1 -C.sub.5 alkyl group, or a C.sub.1 -C.sub.5 alkyl group wherein one or more H is replaced by F, and "n" is an integer of 2 to 9).