Abstract: A fluorometer with at least one light source, a measuring station with a holder for at least one specimen, a measuring head, and an evaluation station with a detector for evaluating emission signals emitted by a specimen. The measuring head is formed by three optical blocks (A, B, C) assembled in a modular manner. A different measurement method is able to be carried out with each optical block (A, B, C). All the optical blocks (A, B, C) operate the same detector.