A new Ba(Ti 1 m x Sn x )O 3 (x=0.15) ferroelectric thin film was applied for uncooled infrared (IR) sensor as a sensing material. The film was prepared by metalorganic decomposition (MOD) with final annealing at 800 . The electrical characteristics such as temperature dependence of capacitance and insulation are very good from viewpoints of temperature coefficient of dielectric constant (TCD) and capacitive operation, where TCD is about 3 %/K at 20 and the resistance is about a few Mohms per 200 m square, respectively. The MOD film was applied to our proposed dielectric bolometer (DB) mode of IR detector that has merits in 1) room temperature operation, 2) chopperless, 3) low power dissipation, and 4) high sensitivity. Finally, the DB-mode operation in the sensor was confirmed on a newly developed device structure, and the resultant voltage sensitivity (R v ) and specific detectivity (D*) were observed to be 0.15 kV/W and 3.5 2 10 8 cmHz 1/2 /W with noise voltage (V n ) of 100 nV, respectively, with the detector size mentioned above. Also, a good stability in IR response against thermal cycling is observed.