Building foundation flatness detection device

The utility model relates to the technical field of building construction detection devices, and discloses a building foundation flatness detection device which comprises a main plate, a semicircular groove is formed in the main plate, an angle line is arranged along the arc-shaped edge of the semicircular groove, a shaft body is rotationally connected to the position, located in the middle of the straight edge, of the semicircular groove, and a pointer is fixedly connected to the lower portion of the shaft body. A storage groove is formed in the portion, away from the semicircular groove, of the main plate, a round rod is fixedly installed between the inner walls of the two sides of the storage groove, the round rod is fixedly sleeved with a rod sleeve, a movable plate is fixedly installed at the bottom of the rod sleeve, and the lower edges of the movable plate and the main plate are each provided with a length line. The device not only can conveniently detect the flatness of the foundation, but also can pl