To provide a titanium bolometer thermal infrared detector capable of increasing a resistance temperature coefficient and enhancing infrared detection sensitivity, and a manufacturing method therefor.

In this titanium bolometer thermal infrared detector having a diaphragm 9 comprising a light receiving part 7 and a support leg 8 for hollow-holding the light receiving part, a titanium bolometer 10 of the light receiving part 7 is protected by sandwiching it with the first silicon nitride film 105 and the second silicon nitride film 106, and oxidation of the titanium bolometer 10 is restrained thereby to provide the thermal light infrared detector of high resistance temperature coefficient and high infrared detection sensitivity. The resistance temperature coefficient is enhanced by optimizing a film forming temperature for the silicon nitride films, in particular, the second silicon nitride film 106 in an upper layer side thereof, and the silicon nitride films are formed to be thin, so as to suppress an increase of thermal conductivity to the minimum by arranging silicon oxide films in an upper layer and a lower layer (or upper layer) thereof.