The key switch includes, a base, a button attached to the base so as to be capable of coming into contact with the base and separating from the base, and a coil spring disposed between the base and the button for urging the button in a direction separating from the base. The coil spring has at least an end turn portion formed at one end, a densely wound portion that is continuous with the end turn portion and compressed in an initial state in which the button is attached to the base so that adjacent windings come into contact with each other, and a coarsely wound portion which is continuous with the densely wound portion and in which a winding pitch is larger than that of the densely wound portion, and in the initial state, adjacent windings are separated from each other.