A vertical seismic isolation device includes: a fixed frame; a movable frame arranged on the fixed frame; a support guide mechanism which allows only vertical movement of the movable frame; and a restoration member which maintains a constant distance between the movable frame and the fixed frame. The support guide mechanism includes: a track rail provided on the fixed frame; a moving block assembled to the track rail through rolling elements; a support leg, which has one end coupled to the moving block and another end coupled to the movable frame, and converts vertical movement of the movable frame into a motion of the moving block; and an auxiliary leg, which is half as long as the support leg, and has one end coupled to the support leg at an intermediate position in a longitudinal direction of the support leg and another end coupled to the fixed frame.