A laser illuminating device and an image display device are provided to enable a removal of speckle noises in a diffraction field and an image field, to uniformly illuminate an illumination plane, and to realize miniaturization. The laser illuminating device 100 includes a laser light source 3 and a first lens 1 including a plurality of microlenses 10, each having a predetermined numerical aperture in an in-plane direction, and each of the microlenses 10 being adapted to expand laser light emitted from the laser light source 3 to thereby superimpose the laser light transmitted through each of the microlenses 10. The laser illuminating device 100 also includes a second lens 2 having an effective diameter larger than an effective diameter of the first lens 1, and compensating for a divergence angle of the laser light expanded by each of the plurality of the microlenses 10.