A method of setting an optimal disposition of a glance sensor included in a mobile terminal comprising: obtaining, via a front camera, a two-dimensional face image of a user; obtaining metadata of the 2D face image, wherein the metadata comprises one or more of an angle of a face of the user, a size of the face, and a location of the face; and obtaining a distance between the glance sensor and the front camera, the distance enabling an area of an overlap region, where a first region representing a range photographable by the front camera overlaps a second region representing a range photographable by the glance sensor, to be the maximum, wherein the distance is smaller than a widthwise length of the mobile terminal, characterized in that the step of obtaining the distance comprises: setting a disposition location of the front camera as an original point, calculating coordinates of a first triangle representing the first region, based on a field of view of the front camera and a maximum photographing distance of the front camera, calculating coordinates of a second triangle representing the second region, based on a field of view of the glance sensor, a maximum photographing distance of the glance sensor, a distance between the front camera and the glance sensor, and a tilting angle of the glance sensor, before the glance sensor is tilted, calculating coordinates of a third triangle representing a third region photographable by the glance sensor, rotation-converting the coordinates of the third triangle, based on the tilting angle of the glance sensor and calculating the coordinates of the second triangle, calculating coordinates of the overlap region based on the coordinates of the first triangle and the coordinates of the second triangle, calculating the area of the overlap region based on the coordinates of the overlap region, and obtaining the distance, enabling the area of the overlap region to be the maximum, between the glance sensor and the front camera by varying a tilting angle of the glance sensor. obtaining, via a front camera, a two-dimensional face image of a user; obtaining metadata of the 2D face image, wherein the metadata comprises one or more of an angle of a face of the user, a size of the face, and a location of the face; and obtaining a distance between the glance sensor and the front camera, the distance enabling an area of an overlap region, where a first region representing a range photographable by the front camera overlaps a second region representing a range photographable by the glance sensor, to be the maximum, wherein the distance is smaller than a widthwise length of the mobile terminal, characterized in that the step of obtaining the distance comprises: setting a disposition location of the front camera as an original point, calculating coordinates of a first triangle representing the first region, based on a field of view of the front camera and a maximum photographing distance of the front camera, calculating coordinates of a second triangle representing the second region, based on a field of view of the glance sensor, a maximum photographing distance of the glance sensor, a distance between the front camera and the glance sensor, and a tilting angle of the glance sensor, before the glance sensor is tilted, calculating coordinates of a third triangle representing a third region photographable by the glance sensor, rotation-converting the coordinates of the third triangle, based on the tilting angle of the glance sensor and calculating the coordinates of the second triangle, calculating coordinates of the overlap region based on the coordinates of the first triangle and the coordinates of the second triangle, calculating the area of the overlap region based on the coordinates of the overlap region, and obtaining the distance, enabling the area of the overlap region to be the maximum, between the glance sensor and the front camera by varying a tilting angle of the glance sensor. setting a disposition location of the front camera as an original point, calculating coordinates of a first triangle representing the first region, based on a field of view of the front camera and a maximum photographing distance of the front camera, calculating coordinates of a second triangle representing the second region, based on a field of view of the glance sensor, a maximum photographing distance of the glance sensor, a distance between the front camera and the glance sensor, and a tilting angle of the glance sensor, before the glance sensor is tilted, calculating coordinates of a third triangle representing a third region photographable by the glance sensor, rotation-converting the coordinates of the third triangle, based on the tilting angle of the glance sensor and calculating the coordinates of the second triangle, calculating coordinates of the overlap region based on the coordinates of the first triangle and the coordinates of the second triangle, calculating the area of the overlap region based on the coordinates of the overlap region, and obtaining the distance, enabling the area of the overlap region to be the maximum, between the glance sensor and the front camera by varying a tilting angle of the glance sensor.