A key switch is provided which includes a key top which is pressed down by optional force and which can move in the press-down direction. The key switch also includes a spring for generating a rebound according to the optional force applied to the key top. The key switch also includes a housing having an elastic member which generates the press-down force against the rebound according to a distance by which the key top moves. The key switch realizes the press-down characteristics in which the inclination of the rebound is zero or negative.