A type of concrete block cutting machine break wire detection device is disclosed, including a positioning bracket, the positioning bracket two sides oppositely arranged with several wire wheels, the positioning bracket two sides oppositely arranged several wire wheels form a group, each wire wheel on the winding of the head and tail connected cut wire, each wire wheel on at least one wire wheel by an electric motor drive, the positioning bracket one side arranged with several horizontal slide rails, each slide rail on the sliding up on each arranged with a slide seat, each wire wheel of the two arranged on the slide seat, the positioning bracket one side horizontally arranged with a screw, the screw on the rotation limit nut, the screw on the sleeve has a pull plate, the pull plate and the slide seat between the spring, the positioning bracket on the slide seat and the pull plate between the light touch switch, the light touch switch and the alarm device and the power series. This type of concrete block cutting machine break wire detection device can alarm when the cut wire is broken, so that the workers can quickly find the broken cut wire, and the cut wire is more convenient to change.