A microwave resonator for or on a textile machine, especially a card, draw frame, combing machine or the like, for attachment to a measuring device for measuring the mass and/or moisture content of textile fiber material conveyable continuously through a resonator chamber, has a housing with wall elements, wherein through-openings in spaced wall elements lying opposite one another are coaxially connected by a tubular element and the interior space of the housing is hollow. In order substantially to simplify manufacture and permit an uninterrupted resonance field, the housing comprises a hollow profile with profile walls in which at least one tubular element connects through-openings in opposite profile walls with each other.