A light guide sheet of the present invention includes a silicone rubber sheet 1 and plural printed mark parts 3a to 3d printed on the front surface of the silicone rubber sheet 1. The silicone rubber sheet 1 has a visible light transmittance of 80 to 99% and is provided at an end face thereof with a light incidence portion 2a allowing light to be incident upon the interior of the silicone rubber sheet 1. The light guide sheet is capable of causing the light incident upon the interior of the silicone rubber sheet 1 from the light incidence portion 2a to be diffused by the printed mark parts 3a to 3d, and pass through the printed mark parts 3a to 3d, thereby guiding the light outside from the printed mark parts 3a to 3d.