A mobile display device includes a display part, a speaker, a microphone, an incoming call-detecting part, a state-detecting part, and a display control part. The display part displays information. The speaker outputs voice. The microphone picks up voice. The incoming call-detecting part detects an incoming call. The state-detecting part detects a positional relationship of the speaker and the microphone. The display control part displays, on the display part, information suggesting the correction of the inclination of the apparatus itself, when the incoming call-detecting part detects an incoming call and the state-detecting part detects that the positional relationship of the speaker and the microphone is in a prescribed positional relationship.