An electronic device includes a light source and an optical sensor. The light source emits a light having a maximum light intensity at a first wavelength A. The optical sensor has a maximum response value at a second wavelength B, and receives a reflected portion of the light that is reflected by an object. The integral value of the light intensity of the light from the wavelength 380 nm to the first wavelength A is I1. The integral value of the light intensity of the light from the first wavelength A to the wavelength 780 nm is I2. The first wavelength A, the second wavelength B, the integral value I1, and the integral value I2 satisfy the following equation: (B−A)*(I2−I1)>0.