A light irradiation substrate (1) includes a flexible substrate (5), first electrical conducting material patterns (15) composed of wirings (2) and a dummy pattern (6) which are provided on a front surface of the flexible substrate (5), and LED chips (4) each of which is mounted on each of the wirings (2), front surfaces of the first electrical conducting material patterns (15) are formed of a reflecting material having total light flux reflectance of 80% or more, and area coverage of the first electrical conducting material patterns (15) at least in a region surrounded by the LED chips (4) is 85% or more.
