An automatic analysis apparatus comprising: an analysis port including a reaction container holding part that holds a reaction container storing a liquid mixture of a sample and a reagent, a light source that emits light to the liquid mixture stored in the reaction container held by the reaction container holding part, and a detector that detects light generated when the light is emitted from the light source to the liquid mixture; and a control unit that controls the analysis port, wherein the sample is analyzed based on information on the detected light, a surface of an inner wall of the reaction container holding part is configured to reflect toward the detector at least a part of the light emitted from the light source, and the control unit executes control so as to emit the light from the light source in the state where the reaction container is not held by the reaction container holding part, to detect the light reflected on the surface of the inner wall of the reaction container holding part by the detector, characterized in that the control unit executes control so as not to use the analysis port for analysis when the result of the detection shows that the detected light is less than a first value determined in advance, and in that the analysis port includes a hole portion that absorbs the light emitted from the light source on a side opposite to the light source with respect to the reaction container, and the hole portion is larger than a range of light emitted from the light source and transmitted through the reaction container in a state where the reaction container is held by the reaction container holding part and is smaller than an emission range of the light emitted from the light source in a state where the reaction container is not held by the reaction container holding part. an analysis port including a reaction container holding part that holds a reaction container storing a liquid mixture of a sample and a reagent, a light source that emits light to the liquid mixture stored in the reaction container held by the reaction container holding part, and a detector that detects light generated when the light is emitted from the light source to the liquid mixture; and a control unit that controls the analysis port, wherein the sample is analyzed based on information on the detected light, a surface of an inner wall of the reaction container holding part is configured to reflect toward the detector at least a part of the light emitted from the light source, and the control unit executes control so as to emit the light from the light source in the state where the reaction container is not held by the reaction container holding part, to detect the light reflected on the surface of the inner wall of the reaction container holding part by the detector, characterized in that the control unit executes control so as not to use the analysis port for analysis when the result of the detection shows that the detected light is less than a first value determined in advance, and in that the analysis port includes a hole portion that absorbs the light emitted from the light source on a side opposite to the light source with respect to the reaction container, and the hole portion is larger than a range of light emitted from the light source and transmitted through the reaction container in a state where the reaction container is held by the reaction container holding part and is smaller than an emission range of the light emitted from the light source in a state where the reaction container is not held by the reaction container holding part.