A bioabsorbable material which is flexible and degradable at a controlled rate, and an in-vivo indwelling device made thereof. The bioabsorbable material is a copolymer composed of an aromatic compound having an ±,²-unsaturated carboxylic group and at least one hydroxyl group as substituents on the aromatic ring, and a polycarbonate or a monomer constituting polycarbonate. Alternatively, it is a copolymer composed of, as the first component, an aromatic compound having an ±,²-unsaturated carboxylic group and at least one hydroxyl group as substituents on the aromatic ring, as the second component, an aromatic compound having an ±,²-unsaturated carboxylic group and at least two hydroxyl groups as substituents on the aromatic ring, and, as the third component, a polycarbonate or a monomer constituting polycarbonate.
