An information processing program that causes a computer to execute a process comprising: acquiring first time-series data that includes measured values regarding movement of legs of a subject in a first period in which the subject travels in a walking manner for each of a plurality of axial directions; acquiring a first index value that relates to value of the measured values of one axial direction of the plurality of axial directions over value of the measured values of another axial direction of the plurality of axial directions for a first section in which the subject swings one of the legs for each of first stride sections that corresponds to one step of the subject in the first period based on the acquired first time-series data; acquiring second time-series data that includes second measured values regarding the movement of the legs of the subject in a second period different from the first period in which the subject travels in the walking manner for each of the plurality of axial directions; acquiring a second index value that relates to value of the measured values of one axial direction of the plurality of axial directions over value of the measured values of another axial direction of the plurality of axial directions for a second section in which the subject swings one of the legs for each of second stride sections that corresponds to one step of the subject in the second period based on the acquired second time-series data; and determining whether or not each of the second stride sections in the second period corresponds to the walking manner, based on the acquired first index value and the acquired second index value, wherein, when a percentage of the second index value for any one of the second stride sections to the first index value is equal to or lower than a predetermined threshold value, it is determined that the any one of the second stride sections corresponds to the walking manner. acquiring first time-series data that includes measured values regarding movement of legs of a subject in a first period in which the subject travels in a walking manner for each of a plurality of axial directions; acquiring a first index value that relates to value of the measured values of one axial direction of the plurality of axial directions over value of the measured values of another axial direction of the plurality of axial directions for a first section in which the subject swings one of the legs for each of first stride sections that corresponds to one step of the subject in the first period based on the acquired first time-series data; acquiring second time-series data that includes second measured values regarding the movement of the legs of the subject in a second period different from the first period in which the subject travels in the walking manner for each of the plurality of axial directions; acquiring a second index value that relates to value of the measured values of one axial direction of the plurality of axial directions over value of the measured values of another axial direction of the plurality of axial directions for a second section in which the subject swings one of the legs for each of second stride sections that corresponds to one step of the subject in the second period based on the acquired second time-series data; and determining whether or not each of the second stride sections in the second period corresponds to the walking manner, based on the acquired first index value and the acquired second index value, wherein, when a percentage of the second index value for any one of the second stride sections to the first index value is equal to or lower than a predetermined threshold value, it is determined that the any one of the second stride sections corresponds to the walking manner.