Fiber laser cutting has been widely used in many industrial applications, but the further improvement is required in the reduction of dross. Recently, the control of laser intensity distributions has been investigated in many laser applications, and some researchers have reported that intensity distribution of laser beam has a possibility to improve the cutting quality. Our previous study revealed that the uniform intensity distribution in the kerf width direction enabled to reduce the dross height, and twin spot beam was obtained by dividing a Gaussian beam with a roof axicon lens to control the power ratio in the kerf width direction. However, twin spot beam setting in the kerf width direction could improve the dross adhesion only in one side. Therefore, twin spot beam was set in the scanning direction, and the proper control of power ratio was investigated in laser cutting experiments for cold rolled steel sheet of 3.2 mm thickness by 3 kW fiber laser with a nitrogen assist gas. A ray tracing analysis and high-speed observation of molten metal ejection made it clear that high intensity of rear beam smoothly ejects molten metal at the lower part of workpiece, and a small ejecting width and the forward slanting ejection of molten metal were important to reduce the dross height. The dross height could be reduced to 16 µm by using the rear beam power of 90 % and the front beam power of 10 %.