The invention discloses a straight angle measuring device. The device comprises a main body and at least one measuring meter connected with the main body. The device is characterized in that the main body comprises a first arm and a second arm, wherein the first arm and the second arm are vertically arranged; the first arm and the second arm are respectively provided with at least one mounting hole in the longitudinal direction; the measuring meter is connected with the main body through the mounting holes; the main body is provided with a positioning part attached to the surface of a measured object; and the first arm and the second arm are provided with weight-reducing grooves. The straight angle measuring device provided by the invention has the advantages of simple structure, accurate measurement, convenient use, low cost and wide application.