An imaging lens assembly, having an optical axis, includes an imaging lens set and a lens holding member. The lens holding member accommodates the imaging lens set for aligning the imaging lens set with the optical axis. The lens holding member includes a plurality of light-blocking structures, which are disposed on an object side of the imaging lens set and surround the optical axis for forming a light passing hole. Each of the light-blocking structures is a straight-line shape and has two end points and one central point, and the central point is closer to the optical axis than each of the two end points thereto. A maximum radius of the light passing hole is defined by a position near each of the two end points, and a minimum radius thereof is defined by a position near the central point.