Rebar diameter detection device for constructional engineering

The utility model relates to the field of detection devices, in particular to a steel bar diameter detection device for constructional engineering. Comprising an inverted-U-shaped buckle plate, a vertical rotating plate is rotationally connected to the front end of the left side of a straight part above the buckle plate, a fixing block is fixed to the upper end of the buckle plate on the left side of the rotating plate, the fixing block blocks the rotating plate, a vertical long groove is formed in the lower portion of the rotating plate, and a longitudinal lifting rod is slidably arranged in the long groove; a fixing sleeve is fixed to the front end of the rotating plate, a vertical supporting rod is arranged in the fixing sleeve in a sliding mode, the lower end of the supporting rod is fixedly connected with the lifting rod, a transverse pointer is fixed to the upper end of the supporting rod, and a vertical ruler is fixed to the position, on the left side of the pointer, of the front end of the rotating pl