To provide a screw device, rich in decorativeness at low cost.

This screw device has a first screw part, a shaft body provided with the first screw part, a second screw part arranged in an upper end part of the shaft body, an expanding slot part arranged in the upper end part of the shaft body, and a head part having a third screw part threadedly engaging with the second screw part, and is characterized by decoration applied to the head part.