PROBLEM TO BE SOLVED: To provide a biological information acquisition system capable of accurately acquiring biological information of an animal.SOLUTION: A biological information acquisition system S is provided with: at least one pressure sensitive part 20； at least one pressure reception part 29 that receives a pressure applied on the pressure sensitive part 20 due to a body motion of an animal and outputs a signal corresponding to the pressure； at least one presence/absence determination part 31 that determines whether the animal is present or not present on the pressure sensitive part 20； and a biological information acquisition part that has an accumulated time determination part 36 that determines whether or not an accumulated time of a presence period, which is from when the presence/absence determination part 31 determines the presence of the animal to when it is determined that the animal is absent for the first time, exceeds a predetermined time, the biological information acquisition part being configured to acquire the biological information of the animal on the basis of the signal outputted from the pressure reception part 29 for each of a plurality of the accumulated presence periods.SELECTED DRAWING: Figure 6
