Abstract: Provided are a belt-like flexible LED light which can use a general surface mounting type LED having a large number of kinds, can be bent in both an orthogonal direction to a light emitting direction and a vertical direction, is long and compact and applies a stress to a circuit board with difficulty, a circuit board capable of implementing the same, and an LED illuminating device using the same. An LED mounting circuit board in which an LED mounting portion 1 having a plurality of LEDs mounted in an array is provided on a central part in a transverse direction of a long belt-like flexible board, both sides in a transverse direction of the LED mounting portion 1 are provided with a first board 2 and a second board 3 having a feed pattern for causing a current to flow to the LEDs which is formed thereon, and the LED mounting portion 1 and the first board 2 and second board 3 are formed to be bendable, and a belt-like flexible LED light using the same are provided.