To provide an illumination device and a showcase device in which the balance of illumination distribution in an illuminated body can be obtained and in which dazzling is hard to be given to a person who looks at the illuminated body from the front.

The illumination device 7 is provided with a light source 13 and a reflector 15 to receive and reflect light of the light source 13, and the reflector 15 has a one-side reflecting face 29 positioned at the object side and the other side reflecting face 31 arranged continuously to the one side reflecting face 29 opposing the other side reflecting face 29, and the one side reflecting face 29 reflects the light received from the light source 13 approximately in parallel parallel, and the other side reflecting face 31 reflects and interrupts the light received from the light source 13.