An on-vehicle communication device adapted to be loaded on a vehicle comprising: a communication unit configured to communicate with a roadside device ; a roadside device position information storage unit configured to store in advance first position information indicating a position of the roadside device ; a vehicle position information acquisition unit adapted to acquire second position information indicating a position of the vehicle ; an approach decision unit adapted to decide whether the vehicle approaches the roadside device on the basis of the first position information stored in the roadside device position information storage unit and the second position information that the vehicle position information acquisition unit acquires; a communication control unit adapted to switch a state of the communication unit from a power-saving state to a non-power-saving state in a case where the approach decision unit decides that the vehicle approaches the roadside device ; and a threshold setting unit adapted to acquire speed information of the vehicle , characterized in that : the communication control unit configured to switch the state of the communication unit from the non-power-saving state to the power-saving state in a case where a duration of a state where electric wave is not received from the roadside device exceeds a time threshold after switching the state of the communication unit from the power-saving state to the non-power-saving state, and the threshold setting unit sets the time threshold in accordance with the speed information. a communication unit configured to communicate with a roadside device ; a roadside device position information storage unit configured to store in advance first position information indicating a position of the roadside device ; a vehicle position information acquisition unit adapted to acquire second position information indicating a position of the vehicle ; an approach decision unit adapted to decide whether the vehicle approaches the roadside device on the basis of the first position information stored in the roadside device position information storage unit and the second position information that the vehicle position information acquisition unit acquires; a communication control unit adapted to switch a state of the communication unit from a power-saving state to a non-power-saving state in a case where the approach decision unit decides that the vehicle approaches the roadside device ; and a threshold setting unit adapted to acquire speed information of the vehicle , characterized in that : the communication control unit configured to switch the state of the communication unit from the non-power-saving state to the power-saving state in a case where a duration of a state where electric wave is not received from the roadside device exceeds a time threshold after switching the state of the communication unit from the power-saving state to the non-power-saving state, and the threshold setting unit sets the time threshold in accordance with the speed information. the communication control unit configured to switch the state of the communication unit from the non-power-saving state to the power-saving state in a case where a duration of a state where electric wave is not received from the roadside device exceeds a time threshold after switching the state of the communication unit from the power-saving state to the non-power-saving state, and the threshold setting unit sets the time threshold in accordance with the speed information. <EOS>