A lens unit includes a plurality of optical elements stacked, each of the plurality of optical elements including a glass substrate as a base, the glass substrates having a same size in respective cross-sections in a direction orthogonal to an optical path, and the optical elements are lens elements with resin lenses disposed on the respective bases, and each of the plurality of optical elements includes an annular recess portion surrounding the optical path and extending through the glass substrate, and a light shielding wall made of a light shielding material charged in the recess portion.