FINGERPRINT INPUT APPARATUS

A fingerprint input apparatus includes scattered light and a two-dimensional image sensor. The scattered light is generated inside a finger having a fingerprint pattern in accordance with external light. The fingerprint pattern is made up of a ridge portion and a valley portion. The two-dimensional image sensor is made of a large number of light-receiving elements arranged in a two-dimensional array. The image of the fingerprint pattern is input to a light-receiving surface of the light-receiving element. The light-receiving element whose light-receiving surface is in substantially contact with the ridge portion detects as the ridge portion a bright portion where the scattered light emerging from the finger reaches at a high intensity. The light-receiving element whose light-receiving surface corresponds to the valley portion via a space detects as the valley portion a dark portion where the scattering light emerging from the finger reaches at a low intensity.