Infrared detection element

This infrared detection element is provided with: a buffer layer (an InAsSb layer) (3); a buffer layer (an InAs layer) (4); and a light-absorption layer (an InAsSb layer)(5). The critical film thickness (hc) of the InAs layer and the thickness (t) of the InAs layer satisfy the relationship hc < t. In such cases, the crystallinity of the InAsSb light-absorption layer (5) and the InAs buffer layer (4) formed upon the buffer layer (3) can be improved.