A projection-type image display device includes a transmissive image display panel having a matrix of pixels arranged at different pitches in different directions perpendicular to each other, and a planar microlens array for converging light emitted by a light source onto the transmissive image display panel. The planar microlens array comprises a substrate and a matrix of microlenses disposed on the substrate for converging the light onto the pixels, respectively, each of the microlenses being of an oblong shape. Each of the microlenses may have a longitudinal axis inclined with respect to an axis of the matrix of pixels to cover the pixel aperture of one of the pixels. The oblong shape of each of the microlenses may be composed of a pair of spaced identical semicircles and a rectangle interconnecting the identical semicircles and having sides of the same length as the diameter of the semicircles. Since the oblong microlenses are shaped to fully cover the pixel apertures of the corresponding pixels, the light from the light source is efficiently converged onto the pixels by the microlenses to produce light display images.