The present invention relates to a device for detecting leaks of liquids or gases caused by temperature variations, pressure variations, wear on the clamping and coupling devices, wear on sealing devices, by corrosive action, among others, in joints between pipes made by flanges (F) and together and basically comprises a strip (1) to be applied to the region of the “gap” (G) between flanges (F) with a pressure sensor (2) and protective caps (3) adapted to a screw head casing (PE) and nuts (P) employed for mounting between flanges (F).