There is provided a respiration estimation method. The respiration estimation method includes a first step (S107) of estimating a breathing rate of a subject based on each of a time-series signal of first data relating to a cardiac function of the subject and a time-series signal of second data relating to an acceleration by a respiratory motion of the subject, a second step (S108) of estimating a breathing rate obtained by filtering noise using a Kalman filter for each of the breathing rate estimated based on the first data and the breathing rate estimated based on the second data, and a third step (S109) of executing weighted averaging processing for the plurality of estimated values of the breathing rates obtained in the second step.
