An information processing device, comprising: a motion information acquisition unit that is configured to acquire motion information detected by a motion detection device that detects a motion of a subject; a storage unit that is configured to store therein the motion information acquired by the motion information acquisition unit; a control unit; wherein the control unit is configured to derive reference motion information on a left half body and reference motion information on a right half body of the subject, based on the motion information in a predetermined period stored by the storage unit; and the control unit is configured to determine whether an abnormal state in which there is a possibility of cerebral infarction in the subject is present based on the reference motion information, and motion information on a left half body and motion information on a right half body of the subject at a detection time subsequent to the predetermined period wherein the motion information includes first motion information in which a motion in the left half body of the subject is detected and second motion information in which a motion in the right half body of the subject is detected, the control unit is configured to respectively compare the first motion information in the reference motion information with the first motion information at the detection time, and the second motion information in the reference motion information with the second motion information at the detection time, wherein, if the control unit has determined that an abnormality is present in one of the half bodies and no abnormality is present in the other half body, the control unit determines that the abnormal state is present, and if the control unit has determined that no abnormality is present in both of the half bodies, the control unit determines that no abnormal state is present, and also if the control unit has determined that the abnormality is present in both of the half bodies, the control unit determines that no abnormal state is present. a motion information acquisition unit that is configured to acquire motion information detected by a motion detection device that detects a motion of a subject; a storage unit that is configured to store therein the motion information acquired by the motion information acquisition unit; a control unit; wherein the control unit is configured to derive reference motion information on a left half body and reference motion information on a right half body of the subject, based on the motion information in a predetermined period stored by the storage unit; and the control unit is configured to determine whether an abnormal state in which there is a possibility of cerebral infarction in the subject is present based on the reference motion information, and motion information on a left half body and motion information on a right half body of the subject at a detection time subsequent to the predetermined period wherein the motion information includes first motion information in which a motion in the left half body of the subject is detected and second motion information in which a motion in the right half body of the subject is detected, the control unit is configured to respectively compare the first motion information in the reference motion information with the first motion information at the detection time, and the second motion information in the reference motion information with the second motion information at the detection time, wherein, if the control unit has determined that an abnormality is present in one of the half bodies and no abnormality is present in the other half body, the control unit determines that the abnormal state is present, and if the control unit has determined that no abnormality is present in both of the half bodies, the control unit determines that no abnormal state is present, and also if the control unit has determined that the abnormality is present in both of the half bodies, the control unit determines that no abnormal state is present.