There is provided an infrared sensor and a holder which is capable of preventing optical filters from being contaminated by adhesives used to fix filters to the detection element (infrared sensor element). A holder 20 included in an infrared sensor includes accommodation parts 21a and 21b that accommodate optical filters, recess parts 23a and 23b that are provided on the opposite surface 20a of the holder 20 which faces the to the infrared sensor element and are placed apart from the accommodation parts 21a and 21b, a groove 25a that is provided on the opposite surface 20a and is placed between the accommodation part 21a and the recess part 23a, and a groove 25b that is provided on the opposite 20a and is placed between the accommodation part 21b and the recess part 23b. The depth d2 of each of the grooves 25a and 25b is greater than the depth d1 of each of the recess parts 23a and 23b. In a process of adhering the infrared sensor element to the holder 20, an adhesive is applied to the recess parts 23a and 23b.