The invention relates to the technical field of road detecting, in particular to a road crack detecting device. The detecting device includes a fixing base, a cross beam is fixed to the fixing base, at least one area-array camera, laser method sensor and vertical acceleration sensor are mounted on the cross beam, the fixing base is mainly composed of sucking disc bottoms, supporting arms, a transverse adjusting shaft, a rotating arm, a longitudinal adjusting knob and a 360 degree adjuster, the two parallel supporting arms are vertically fixed to the sucking disc bottoms, the transverse adjusting shaft are transversely connected between the two supporting arms in a penetrating mode, the lower end of the rotating arm sleeves the transverse adjusting shaft, the longitudinal adjusting knob ismounted at the upper end of the rotating arm longitudinally and horizontally, the lower end of the 360 degree adjuster is movably mounted at the upper end of the rotating arm, the cross beam is horizontally fixed to the upper end of the 360 degree adjuster, and the cross beam and the 360 degree adjuster keep perpendicularly. The road crack detecting device can be directly mounted on a vehicle engine hood and is suitable for various vehicle models, the cost is saved, and using is convenient; and a mode of seamless connection is adopted, all-directional detecting and image recording are achieved.