According to one embodiment, an imaging lens includes a first optical system and a microlens array. The first optical system includes an optical axis. The microlens array is provided between the first optical system and an imaging element. The microlens array includes microlens units provided in a first plane. The imaging element includes pixel groups. Each of the pixel groups includes pixels. The microlens units respectively overlap the pixel groups when projected onto the first plane. The first optical system includes an aperture stop, and first, second, and third lenses. The first lens is provided between the aperture stop and the microlens array, and has a positive refractive power. The second lens is provided between the first lens and the microlens array, and has a negative refractive power. The third lens is provided between the second lens and the microlens array, and has a positive refractive power.