A biological sample analysis device for analysing light generated by an organism-derived substance contained in a sample, the biological sample analysis device comprising: a holder that holds multiple containers containing the sample; a photodetector that is fixed at a predetermined position; a holder driving mechanism configured to move the holder to position each of the containers held in the holder at a detection position by the photodetector in sequence; a light shielding mechanism configured to, while guiding light emitted from the sample in a container at the detection position to the photodetector, prevent light emitted from the sample in the other containers from being guided to the photodetector; and a dispensing mechanism configured to, into the containers at the detection position from above, introduce a reagent that reacts with the organism-derived substance to generate light, characterized in that the light shielding mechanism comprises: multiple container side light shielding parts, each of the multiple container side light shielding parts is provided to each of the containers and is configured to move with each of the containers, and to cover upper parts of each of the containers; and a movable side light shielding part configured to move back and forth with respect to the container at the detection position, as well as to cover a lower part of the container at the detection position; wherein the movable side light shielding part includes a reflector configured to guide the light emitted from the sample in the container at the detection position to the photodetector. a holder that holds multiple containers containing the sample; a photodetector that is fixed at a predetermined position; a holder driving mechanism configured to move the holder to position each of the containers held in the holder at a detection position by the photodetector in sequence; a light shielding mechanism configured to, while guiding light emitted from the sample in a container at the detection position to the photodetector, prevent light emitted from the sample in the other containers from being guided to the photodetector; and a dispensing mechanism configured to, into the containers at the detection position from above, introduce a reagent that reacts with the organism-derived substance to generate light, characterized in that the light shielding mechanism comprises: multiple container side light shielding parts, each of the multiple container side light shielding parts is provided to each of the containers and is configured to move with each of the containers, and to cover upper parts of each of the containers; and a movable side light shielding part configured to move back and forth with respect to the container at the detection position, as well as to cover a lower part of the container at the detection position; wherein the movable side light shielding part includes a reflector configured to guide the light emitted from the sample in the container at the detection position to the photodetector. multiple container side light shielding parts, each of the multiple container side light shielding parts is provided to each of the containers and is configured to move with each of the containers, and to cover upper parts of each of the containers; and a movable side light shielding part configured to move back and forth with respect to the container at the detection position, as well as to cover a lower part of the container at the detection position; wherein the movable side light shielding part includes a reflector configured to guide the light emitted from the sample in the container at the detection position to the photodetector.