An information processing system comprising a first information processing device and a second information processing device for connecting via a network to the first information processing device which is enabled to recognize action of a user on a basis of an output of a sensor incorporated in said first information processing device and to transmit action information indicating the recognized action of the user together with information indicating a present location, said second information processing device comprising: predicting means for predicting one of a time of arrival at a predetermined destination of the user of said first information processing device and a time to be taken before the user of said first information processing device arrives at said predetermined destination on a basis of said action information, said first information processing device being enabled to perform the recognition of the action of the user of the first information processing device based on a walk frequency, a walk intensity and a gravity axis extracted from data supplied by an acceleration sensor, and an angle of rotation about said gravity axis extracted from data supplied by a gyro sensor, and comprising the information processing system further comprises a feature extraction processing unit, an action recognition processing unit and a Hidden Markov Mode, HMM, Database, DB,, wherein the feature extraction processing unit extracts features from acceleration sensor data supplied from the acceleration sensor and gyro sensor data supplied from the gyro sensor, and outputs feature data indicating the extracted features to the action recognition processing unit, and wherein the action recognition processing unit accumulates a predetermined amount of the feature data supplied from the feature extraction processing unit, and recognizes the action of the user referring to the HMM DB, said predicting means of said second information processing device being adapted to display one of the predicted time of arrival at the predetermined destination of the user of said first information processing device and the time to be taken before the user of said first information processing device arrives at said predetermined destination together with a history of actions of the user of said first information processing device and together with the present position and present action of the user of the first information processing device, and to predict the time of arrival from a distance from the present position of the user of the first information processing device and a velocity at which the user of the first information processing device is heading toward the predetermined destination. predicting means for predicting one of a time of arrival at a predetermined destination of the user of said first information processing device and a time to be taken before the user of said first information processing device arrives at said predetermined destination on a basis of said action information, said first information processing device being enabled to perform the recognition of the action of the user of the first information processing device based on a walk frequency, a walk intensity and a gravity axis extracted from data supplied by an acceleration sensor, and an angle of rotation about said gravity axis extracted from data supplied by a gyro sensor, and comprising the information processing system further comprises a feature extraction processing unit, an action recognition processing unit and a Hidden Markov Mode, HMM, Database, DB,, wherein the feature extraction processing unit extracts features from acceleration sensor data supplied from the acceleration sensor and gyro sensor data supplied from the gyro sensor, and outputs feature data indicating the extracted features to the action recognition processing unit, and wherein the action recognition processing unit accumulates a predetermined amount of the feature data supplied from the feature extraction processing unit, and recognizes the action of the user referring to the HMM DB, said predicting means of said second information processing device being adapted to display one of the predicted time of arrival at the predetermined destination of the user of said first information processing device and the time to be taken before the user of said first information processing device arrives at said predetermined destination together with a history of actions of the user of said first information processing device and together with the present position and present action of the user of the first information processing device, and to predict the time of arrival from a distance from the present position of the user of the first information processing device and a velocity at which the user of the first information processing device is heading toward the predetermined destination.