A mobile radio device capable of receiving a radio signal whose frequency band switches, includes a setting unit that when the frequency band of the radio signal is a first frequency band, sets a first threshold corresponding to the first frequency band, and that when the frequency band switches from the first frequency band to a second frequency band different from the first frequency band, sets for a given period, a third threshold that is between the first threshold and a second threshold corresponding to the second frequency band and subsequently sets the second threshold; and a determining unit that determines a travel speed of the mobile radio device, based on a comparison of a moving average obtained by temporally accumulating variations of estimates of propagation characteristics of the radio signal and averaging the accumulated variations by a moving average method using a threshold set by the setting unit.