An LED illumination device includes LED lamp modules 34 coupled in a vertical direction. Each of said LED lamp modules 34 includes a base 12, a bus bar circuit 35 formed on the base 12, and a cover 25 connected to the base 12 to cover the bus bar circuit 35. A locking frame 14 (coupling portion) to be coupled with the upper LED lamp module 34 is formed on said base 12. A locking arm 32 (mating coupling portion) to be coupled with said locking frame 14 on the base 12 of the lower LED lamp module 34 is formed on said cover 25. Further, a guiding groove 18, into which said locking arm 34 is inserted, is formed on said base 12 near the locking frame 14, and a guiding hole 27, into which said locking frame 14 is inserted, is formed on the cover 25 near the locking arm 32.