To provide a warp tension-detecting device capable of detecting the tension at a high accuracy by a simple structure.

This warp tension-detecting device has a beam-like detecting member 30 fixed to a prescribed position in a cantilever beam state, a strain gauge 31 installed in the beam-like detecting member 30, a swingable member 25 attached to the beam-like detecting member 30 so as to be freely swung, and a tension roll 36 held by the swingable member 2 and allowing a warp yarn 1 to be hung thereon. The line passing the fulcrum for the swing of the swingable member 25, and the attaching part of the tension roll 36 is formed so as to cross the extension direction of the beam-like detecting member 30. A tension deviation-regulating member 22 moving so as to absorb the deviation of the tension of the warp yarn 1 by the swing of the tension roll 36 is connected to the swingable member 25.