The invention provides a circuit board attaching device, and the device comprises a base body, a pedestal, and a stitching steel sheet. The base body is provided with positioning gaps, and the pedestal is provided with positioning projections which are corresponding to the positioning gaps in a one-to-one manner. The positioning projections correspondingly pass through the positioning gaps to form a plurality of accommodation grooves on the surface of the base body. Each accommodation groove is used for placing a first circuit board and a second circuit board, which are attached together. The base body is also connected with a connection part, and achieves the fixed attaching with the stitching steel sheet through the connection part, thereby enabling the first and second circuit boards attached together to be fixed on each accommodation groove. The device achieves the fixed attaching of the first and second circuit boards and the bonding pad alignment at the attaching part, so as to achieve the welding of the two circuit boards. The device is good in welding effect. Meanwhile, the device reduces the technological process, improves the production efficiency, and saves the cost.