Carbon fiber reinforced thermo plastics (CFRTP), which is expected to reduce the weight of transportations and is made higher speed and lower cost than these of CFRP, was cut by a CO_2 gas laser (10.6μm, 800W, CW(continuous wave), 1 m/min), single-mode fiber laser (1.07μm, 300W,350W or 2000W, CW, 1-7m/min) and machining with milling. Although the high-power laser cutting processes make it possible to improve cutting rate of CFRTP, the laser-cut specimens clearly showed a thermal damage with a heat-affected zone (HAZ) identified by a micro X-ray CT observation. These laser-cut specimens were lower tensile strength than milling-cut specimens. From the results of thermo-elastic stress analysis, low-stress field was generated in the HAZ, led to the cause of strength degradation.