A bus-bar for assembling a capacitor device is disclosed, which is capable of improving the environment of a soldering operation for the bus-bar being soldered to a capacitor device, reducing the inferior rate of the capacitor device while improving the quality of the capacitor device, and reducing the weight of the capacitor module, in soldering the bus-bar to capacitor devices. The lead frame attached to polar plates by soldering is formed thinner than the other parts of the bus-bar, and opening parts having an oval or polygonal shape are formed on a surface of the bus-bar so that two adjoining capacitor devices can be exposed. The lead frame is formed in the opening in order for soldering with the polar plates of the capacitor device.