An agricultural harvesting machine has a measurement device for investigating a crop flow conveyed through the harvesting machine. The measurement device includes at least one optical detection unit disposed at the crop flow for detecting light reflected by the crop and an evaluation unit for evaluating the spectrum of the detected light in order to derive properties of the crop. The evaluation unit is disposed at a position of the harvesting machine that is decoupled from mechanical loading by the crop flow to the greatest extent possible and is connected to the detection unit by way of at least one optical waveguide.