A terminal device includes: a time information receiving unit which receives measured time and an estimated error of another terminal device; an estimated error calculating unit which calculates an error containing the estimated error of another terminal device received by the time information receiving unit as an updating-use estimated error; and a time updating unit which, when the updating-use estimated error calculated by the estimated error calculating unit is smaller than an estimated error stored in an estimated error memory unit, stores the updating-use estimated error calculated by the estimated error calculating unit in the estimated error memory unit thus updating the estimated error stored in the estimated error memory unit, and adjusts a measured time measured by a time measuring unit in response to the measured time of another terminal device received by the time information receiving unit.