The present invention addresses the problem of providing a drug formulation material with which localized sustained release of a drug at any site in the body is possible and which has good bioabsorption and is absorbed and broken down by the body after sustained release of the drug. A drug formulation material that has an exceedingly high sustained release effect and that solves the foregoing problem was successfully developed by dissolving a biodegradable resin and a drug in a solvent to prepare a spinning solution and spinning fibers from the spinning solution by electrospinning.
