8. A schedule management method according to claim 7 , further comprising: acquiring information from a sensor; and estimating contexts on the basis of the information from the sensor.
8. A schedule management method according to claim 7 , further comprising: acquiring information from a sensor; and estimating contexts on the basis of the information from the sensor. 9. A schedule management method according to claim 8 , wherein said acquiring includes detecting information signals including one of latitude, longitude, and gateway address, from the outside, and said estimating includes estimating a place-context on the basis of the information signals.