A display device comprising: a light-emitting display adapted to change display brightness a luminance detection means adapted to detect ambient luminance; and a control means adapted to control the display brightness of the light-emitting display in accordance with a current luminance value calculated based on a detection result of the luminance detection means, wherein the control means is configured to: determine that there is no luminance change when an absolute value of a difference between the current luminance value and a directly-preceding luminance value is less than a predetermined threshold value; and determine (S17,S18) that there is a luminance change when the absolute value of the difference between the current luminance value and the directly-preceding luminance value is equal to or greater than the predetermined threshold value; characterized in that the control means is further configured to: adjust the display brightness of the light-emitting display in accordance with the current luminance value, when it is determined that there is a luminance change successively in a first number of times, and to adjust the display brightness of the light-emitting display in accordance with the current luminance value when it is determined that there is no luminance change successively in a second number of times greater than the first number of times. a light-emitting display adapted to change display brightness a luminance detection means adapted to detect ambient luminance; and a control means adapted to control the display brightness of the light-emitting display in accordance with a current luminance value calculated based on a detection result of the luminance detection means, wherein the control means is configured to: determine that there is no luminance change when an absolute value of a difference between the current luminance value and a directly-preceding luminance value is less than a predetermined threshold value; and determine (S17,S18) that there is a luminance change when the absolute value of the difference between the current luminance value and the directly-preceding luminance value is equal to or greater than the predetermined threshold value; determine that there is no luminance change when an absolute value of a difference between the current luminance value and a directly-preceding luminance value is less than a predetermined threshold value; and determine (S17,S18) that there is a luminance change when the absolute value of the difference between the current luminance value and the directly-preceding luminance value is equal to or greater than the predetermined threshold value; characterized in that the control means is further configured to: adjust the display brightness of the light-emitting display in accordance with the current luminance value, when it is determined that there is a luminance change successively in a first number of times, and to adjust the display brightness of the light-emitting display in accordance with the current luminance value when it is determined that there is no luminance change successively in a second number of times greater than the first number of times. adjust the display brightness of the light-emitting display in accordance with the current luminance value, when it is determined that there is a luminance change successively in a first number of times, and to adjust the display brightness of the light-emitting display in accordance with the current luminance value when it is determined that there is no luminance change successively in a second number of times greater than the first number of times.