This paper reports a 4.7-μm mid-wave infrared quantum cascade laser based on double active region structure with a ridge width of 9.5 μm, which can achieve continuous single transverse mode operation at room temperature. By inserting 0.8-μm InP, the original single active region is transformed into a double active region structure, which can significantly reduce the peak temperature of the device's active region and suppress the generation of higher-order transverse modes. At a temperature of 288 K, the device with a double active region structure with a cavity length of 5 mm has a threshold current density of 1.14 kA/cm², a continuous output power of 0.706 W, a fast axis divergence angle of 27.3°, and a slow axis divergence angle of 18.1°. Compared with conventional devices with a single active region structure, the devices with a double active region structure have no degradation in their maximum optical output power and show a significant improvement in the beam quality in the slow axis direction of the device. These results provide a solution to the problem of the slow axis beam quality of high-power mid-wave quantum cascade lasers.