A wearable device comprising: a sensor unit including a heart rate sensor and a motion sensor, and a control unit, wherein the heart rate sensor is configured to measure a heart rate of a user and output a measured result to the control unit, and wherein the motion sensor includes at least one acceleration sensor and is configured to detect a change in acceleration caused according to an operation of the user, and output a detection result to the control unit; wherein the wearable device is configured to: acquire acceleration time-series data and heart rate time-series data, wherein the wearable device further comprises: a classification unit configured to: classify to which cluster of a plurality of clusters the acceleration time-series data and the heart rate time-series data belong based on a comparison between the heart rate time-series data with a model associated with the cluster, wherein the heart rate time series data which are similar to each other belong to the same cluster, and wherein for heart rate time series data belonging to the same cluster, consumed energy can be estimated from the heart rate time-series data by using the model as a common model; and an estimation unit configured to: input the acceleration time-series data and the heart rate time-series data corresponding to the classified cluster into an estimation database; and estimate consumed energy time-series data on the basis of the model. a sensor unit including a heart rate sensor and a motion sensor, and a control unit, wherein the heart rate sensor is configured to measure a heart rate of a user and output a measured result to the control unit, and wherein the motion sensor includes at least one acceleration sensor and is configured to detect a change in acceleration caused according to an operation of the user, and output a detection result to the control unit; wherein the wearable device is configured to: acquire acceleration time-series data and heart rate time-series data, wherein the wearable device further comprises: a classification unit configured to: classify to which cluster of a plurality of clusters the acceleration time-series data and the heart rate time-series data belong based on a comparison between the heart rate time-series data with a model associated with the cluster, wherein the heart rate time series data which are similar to each other belong to the same cluster, and wherein for heart rate time series data belonging to the same cluster, consumed energy can be estimated from the heart rate time-series data by using the model as a common model; and an estimation unit configured to: input the acceleration time-series data and the heart rate time-series data corresponding to the classified cluster into an estimation database; and estimate consumed energy time-series data on the basis of the model. classify to which cluster of a plurality of clusters the acceleration time-series data and the heart rate time-series data belong based on a comparison between the heart rate time-series data with a model associated with the cluster, wherein the heart rate time series data which are similar to each other belong to the same cluster, and wherein for heart rate time series data belonging to the same cluster, consumed energy can be estimated from the heart rate time-series data by using the model as a common model; and an estimation unit configured to: input the acceleration time-series data and the heart rate time-series data corresponding to the classified cluster into an estimation database; and estimate consumed energy time-series data on the basis of the model. input the acceleration time-series data and the heart rate time-series data corresponding to the classified cluster into an estimation database; and estimate consumed energy time-series data on the basis of the model.