An infrared detector includes a detecting element, a first electrode, a second electrode, and a covering structure. The detecting element defines an absorbing part and a non-absorbing part. The detecting element includes a first end and a second end opposite with the first end. The first end is disposed in the absorbing part. The second end is disposed in the non-absorbing part. The first electrode is electrically connected with the first end. The second electrode is electrically connected with the second end. The covering structure covers the non-absorbing part. The detecting element further includes a carbon nanotube layer. The carbon nanotube layer includes a plurality of carbon nanotubes disposed uniformly.