Provided is a mobile information device which can prevent erroneous inputs in situations where conventional mobile information devices cannot prevent erroneous inputs. Two proximity sensors 110 are provided on a front surface 102 of a mobile information device 100. The two proximity sensors 110 are separated from one another by a distance equivalent to at least one key 105, and are each adjacent to at least one of the keys 105. The mobile information device 100 blocks execution of processing in response to key operations when both of the proximity sensors 110 detect a state of proximity of a sensing target, such as a human body. As a result, erroneous inputs on the keys 105 caused by contact with hands or face can be prevented.