A mobile terminal device comprising: a communication processor arranged to conduct wireless communication processing; an operation unit arranged to receive an instruction input from a user for selecting a communication contact; a displacement detector (131, 132, 133) arranged to detect a magnitude of displacement in orientation of the mobile terminal device; and a controller arranged to cause the communication processor to conduct the wireless communication with the selected communication contact according to the detected magnitude of displacement, wherein the controller is arranged to cause the communication processor to conduct the wireless communication with the selected communication contact based on whether the magnitude of displacement detected by the displacement detector is within a predetermined range of given magnitudes of displacement, wherein when the magnitude of displacement detected by the displacement detector (131, 132, 133) is within the predetermined range of given magnitudes of displacement, the displacement detector is arranged to determine that the user has brought the mobile terminal device up to an ear of the user, and the controller is arranged to cause the communication processor to automatically conduct the wireless communication as a telephone call with the selected communication contact, wherein when the magnitude of displacement detected by the displacement detector is not within the predetermined range of given magnitudes of displacement, the controller is arranged to cause the communication processor to automatically conduct the wireless communication as an electronic message, and the mobile terminal device is configured to perform a plurality of applications for sending the electronic message, and when the displacement detector determines that the user has not brought the mobile terminal device up to an ear of the user the controller is arranged to cause the communication processor to automatically conduct the wireless communication as said electronic message using the most frequently used application of the plurality of applications. a communication processor arranged to conduct wireless communication processing; an operation unit arranged to receive an instruction input from a user for selecting a communication contact; a displacement detector (131, 132, 133) arranged to detect a magnitude of displacement in orientation of the mobile terminal device; and a controller arranged to cause the communication processor to conduct the wireless communication with the selected communication contact according to the detected magnitude of displacement, wherein the controller is arranged to cause the communication processor to conduct the wireless communication with the selected communication contact based on whether the magnitude of displacement detected by the displacement detector is within a predetermined range of given magnitudes of displacement, wherein when the magnitude of displacement detected by the displacement detector (131, 132, 133) is within the predetermined range of given magnitudes of displacement, the displacement detector is arranged to determine that the user has brought the mobile terminal device up to an ear of the user, and the controller is arranged to cause the communication processor to automatically conduct the wireless communication as a telephone call with the selected communication contact, wherein when the magnitude of displacement detected by the displacement detector is not within the predetermined range of given magnitudes of displacement, the controller is arranged to cause the communication processor to automatically conduct the wireless communication as an electronic message, and the mobile terminal device is configured to perform a plurality of applications for sending the electronic message, and when the displacement detector determines that the user has not brought the mobile terminal device up to an ear of the user the controller is arranged to cause the communication processor to automatically conduct the wireless communication as said electronic message using the most frequently used application of the plurality of applications.