A notifying method executed by a computer, the notifying method comprising: receiving a first time point at which an onset of disease is confirmed in a livestock animal among a livestock animal group, and a disease name of the disease afflicting the livestock animal; identifying disease duration corresponding to the received disease name of the disease afflicting the livestock animal, by referring to a first storage unit that stores a disease name of a disease and disease duration of the disease in a correlated manner; acquiring from a second storage unit that stores for respective time slots of each date, measurement results of a step count of another livestock animal different from the livestock animal in the livestock animal group, a measurement result of the other livestock animal for a first time slot that includes the first time point and a measurement result of the other livestock animal for a second time slot that includes a second time point traced back from the first time point, at least by a period of the identified disease duration; determining whether the disease afflicting the livestock animal is afflicting the other livestock animal, based on the acquired measurement result of the other livestock animal for the first time slot, the acquired measurement result of the other livestock animal for the second time slot, and a threshold value related to the step count specific to the disease afflicting the livestock animal; and outputting a disease name of the disease of the livestock animal and identification information of the other livestock animal, upon determination that the disease afflicting the livestock animal is afflicting the other livestock animal. receiving a first time point at which an onset of disease is confirmed in a livestock animal among a livestock animal group, and a disease name of the disease afflicting the livestock animal; identifying disease duration corresponding to the received disease name of the disease afflicting the livestock animal, by referring to a first storage unit that stores a disease name of a disease and disease duration of the disease in a correlated manner; acquiring from a second storage unit that stores for respective time slots of each date, measurement results of a step count of another livestock animal different from the livestock animal in the livestock animal group, a measurement result of the other livestock animal for a first time slot that includes the first time point and a measurement result of the other livestock animal for a second time slot that includes a second time point traced back from the first time point, at least by a period of the identified disease duration; determining whether the disease afflicting the livestock animal is afflicting the other livestock animal, based on the acquired measurement result of the other livestock animal for the first time slot, the acquired measurement result of the other livestock animal for the second time slot, and a threshold value related to the step count specific to the disease afflicting the livestock animal; and outputting a disease name of the disease of the livestock animal and identification information of the other livestock animal, upon determination that the disease afflicting the livestock animal is afflicting the other livestock animal.