The invention relaters to a device (100) for biological analysis by measurement of photoluminescence in a fluid in a measurement tank (111). This device (100) comprises at least two light sources (121, 131) adapted to emit in different spectral areas respectively appropriate for measurement of absorption and fluorescence, and a sensor device (140) comprising a sensor (141), an optical system (142), and filter means (144), which three elements are mutualized in accordance with the invention to enable absorption and/or fluorescence to be measured. In accordance with the invention the internal gain of the sensor (141) is configurable to enable the fluorescence and absorption measurements to be executed sequentially.