The present invention provides theophylline sustainedrelease particles which contain a polyglycerol fatty acid esteras a matrix base material, which have a homogenous nucleusparticle structure, which can effectively mask the unpleasanttaste of medicaments, and which exhibit an excellent sustainedmedicament releasability (dissolvability) and outstanding storagestability. In particular, the present invention provides, amongother things, a method for preparing theophylline sustainedrelease particles comprising the steps of heating a matrix basematerial containing a polyglycerol fatty acid ester, theophyllineand ethyl cellulose to give a molten mixture； spray-cooling themolten mixture to obtain spherical core particles having anaverage particle diameter of 250 µm or less； and applying fineparticles to the core particles by fusion coating.
