Track straightness measuring instrument

The utility model provides a track straightness measuring instrument, and relates to the technical field of track detection. According to the track flatness measuring instrument, when the track flatness measuring instrument works, the track flatness measuring instrument can move along the first side track of the track through the first rolling mechanism at the bottom of the top face. At the moment, a plurality of distance sensors, of which the top surface and/or the first side surface are arranged on the same straight line at intervals, collect the distance measured value of the rail surface or one side of the corresponding first side rail according to a preset sampling step length, and the process of collecting the distance measured value is not interrupted; the acquired distance measured value is high in continuity, high in reliability and high in acquisition efficiency; in addition, the plurality of distance sensors are arranged on the same straight line at intervals, so that the reliability of the acquire