A night image display apparatus, comprising: an optical pulse output unit configured to output optical pulses to two external objects at a first time interval for a specific time (t); a photographing unit provided with an image sensor including a plurality of gates; a display unit configured to output a final image obtained by synthesizing a plurality of images; and a controller configured to: activate a first gate for a first time at a second time interval and acquire a first gate image by using optical pulses reflected from the external objects, activate a second gate for a second time at the second time interval and acquire a second gate image by using the optical pulses reflected from the external objects, wherein the second time is shorter than the first time, calculate a light quantity ratio for each pixel of the first gate image and the second gate image, calculate distance information indicating distances of the apparatus from the external objects based on the light quantity ratios and a distance-related light quantity ratio stored in a memory of the device, generate the final image based on the distance information using the first gate image and the second gate image such that images of the external objects included in the final image are formed with a substantially similar brightness, and control the display unit to display the final image. an optical pulse output unit configured to output optical pulses to two external objects at a first time interval for a specific time (t); a photographing unit provided with an image sensor including a plurality of gates; a display unit configured to output a final image obtained by synthesizing a plurality of images; and a controller configured to: activate a first gate for a first time at a second time interval and acquire a first gate image by using optical pulses reflected from the external objects, activate a second gate for a second time at the second time interval and acquire a second gate image by using the optical pulses reflected from the external objects, wherein the second time is shorter than the first time, calculate a light quantity ratio for each pixel of the first gate image and the second gate image, calculate distance information indicating distances of the apparatus from the external objects based on the light quantity ratios and a distance-related light quantity ratio stored in a memory of the device, generate the final image based on the distance information using the first gate image and the second gate image such that images of the external objects included in the final image are formed with a substantially similar brightness, and control the display unit to display the final image. activate a first gate for a first time at a second time interval and acquire a first gate image by using optical pulses reflected from the external objects, activate a second gate for a second time at the second time interval and acquire a second gate image by using the optical pulses reflected from the external objects, wherein the second time is shorter than the first time, calculate a light quantity ratio for each pixel of the first gate image and the second gate image, calculate distance information indicating distances of the apparatus from the external objects based on the light quantity ratios and a distance-related light quantity ratio stored in a memory of the device, generate the final image based on the distance information using the first gate image and the second gate image such that images of the external objects included in the final image are formed with a substantially similar brightness, and control the display unit to display the final image.