A device and a method for curing plastic moldings are particularly suited for curing hearing aid housings. A light source emits curing light and a holder, at least partially transparent to curing light, holds the plastic moldings. The holder has an elongate light guiding element, which is transparent to curing light, which has an emission portion for emitting curing light in a number of spatial directions, and which is formed in such a way that at least the emission portion can protrude into a convex curvature or an interior space of a plastic molding that is being held by the holder. The light guiding element guides curing light emitted from the light source to the emission portion and emits from there. The light guiding element may have a holding portion for holding the plastic molding. The holding portion and the emission portion may spatially overlap. The method includes a step of irradiating the plastic molding with curing light simultaneously on the outside and the inside by the light source and by the light guiding element. Particularly uniform curing without localized temperature peaks is achieved.