An electronic device includes a light source, a light sensor, and a controller that senses an amount of a coarse ambient light by turning off the light source and performing sensing in a coarse mode by using the light sensor and senses an amount of a fine ambient light by performing sensing in a fine mode by using the light sensor. The controller senses an amount of a target light by turning on the light source and performing sensing by using the light sensor while the light source emits a light, and outputs information based on the amount of the coarse ambient light, the amount of the fine ambient light, and the amount of the target light.