A laser processing machine comprising: a laser head configured to irradiate a workpiece with laser beam; a belt conveyor provided away in an irradiation direction of the laser beam; and a control unit configured to control operations of the laser head and the belt conveyor, wherein the laser head is provided above the workpiece and the belt conveyor is provided below the workpiece, the laser head is configured to be movable along at least a conveying direction of the belt conveyor and an inclined direction to the conveying direction of the belt conveyor, the control unit is configured to determine whether or not a condition of a melting prevention run is satisfied, and to execute, in a case where it is determined that the condition of the melting prevention run is satisfied, the melting prevention run to at least one of the laser head and the belt conveyor, the melting prevention run is a run to avoid a relative moving speed of the laser head and the belt conveyor turning to zero, and characterized in that the condition of the melting prevention run contains: a condition that a moving direction of the laser head and the conveying direction of the belt conveyor during the irradiation with the laser beam having a relationship of the following (i) or (ii); and a condition that the moving speed of the laser head is within a preset range to the rotating speed of the belt conveyor during the irradiation with the laser beam, (i) in a case where the conveying direction of the belt conveyor agrees with the moving direction of the laser head, (ii) in a case where the moving direction of the laser head is the inclined direction to the conveying direction of the belt conveyor, and a moving speed of the laser head in orthogonal to the conveying direction of the belt conveyor is less than or equal to a preset speed. a laser head configured to irradiate a workpiece with laser beam; a belt conveyor provided away in an irradiation direction of the laser beam; and a control unit configured to control operations of the laser head and the belt conveyor, wherein the laser head is provided above the workpiece and the belt conveyor is provided below the workpiece, the laser head is configured to be movable along at least a conveying direction of the belt conveyor and an inclined direction to the conveying direction of the belt conveyor, the control unit is configured to determine whether or not a condition of a melting prevention run is satisfied, and to execute, in a case where it is determined that the condition of the melting prevention run is satisfied, the melting prevention run to at least one of the laser head and the belt conveyor, the melting prevention run is a run to avoid a relative moving speed of the laser head and the belt conveyor turning to zero, and characterized in that the condition of the melting prevention run contains: a condition that a moving direction of the laser head and the conveying direction of the belt conveyor during the irradiation with the laser beam having a relationship of the following (i) or (ii); and a condition that the moving speed of the laser head is within a preset range to the rotating speed of the belt conveyor during the irradiation with the laser beam, (i) in a case where the conveying direction of the belt conveyor agrees with the moving direction of the laser head, (ii) in a case where the moving direction of the laser head is the inclined direction to the conveying direction of the belt conveyor, and a moving speed of the laser head in orthogonal to the conveying direction of the belt conveyor is less than or equal to a preset speed. (i) in a case where the conveying direction of the belt conveyor agrees with the moving direction of the laser head, (ii) in a case where the moving direction of the laser head is the inclined direction to the conveying direction of the belt conveyor, and a moving speed of the laser head in orthogonal to the conveying direction of the belt conveyor is less than or equal to a preset speed.