In this research, the effect of the laser intensity of IR fiber laser in the hybrid laser welding was revealed. Pure copper is used for motor coil of electric vehicles due to its excellent thermal and electrical conductivity. In the manufacturing process of it, high process speed and low heat input welding of pure copper wire is needed to realize enhancement of motor performance. Hereby, a high-quality laser welding of pure copper wires, called hairpin welding, is demanded. Generally, a IR fiber laser at a wavelength around 1000 nm is widely used for welding. However, pure copper has low light absorption rate for that wavelength. Additionally, the light absorption rate of copper for IR laser changes drastically due to phase change from solid to liquid. These properties cause low processing efficiency and unstable welding dynamics. On the other hand, pure copper has high light absorption rate at a wavelength of 450 nm. Thus, a blue diode laser is attracting attention for a highly efficient laser welding of pure copper. However, the output power and the beam-quality of blue diode laser are inferior to conventional fiber laser. Due to this, high-speed hairpin welding of pure copper wires is difficult only with a blue diode laser. To solve these problems, a hybrid laser welding which combines a blue diode laser with a IR fiber laser was employed. From previous research, it was reported that the molten volume of pure copper wire with the IR fiber laser increased by combining a blue diode laser. In this research, to achieve further increase in molten volume of copper, the effect of laser intensity of the IR fiber laser in the hybrid laser was investigated. As a result, the molten volume of copper wire increased with increase of the laser intensity for the IR fiber laser.