A peg press-fitting structure for a connector includes a peg which is made from a metal plate to fix a housing of the connector to a circuit board, and which is attached to the housing by being press-fitted from the distal end of the peg into a peg attaching slot of the housing of the connector. The housing is provided with an end wall where an entrance of the peg attaching slot opens. A press-fitting position regulating projection, which regulates the press-fitting position of the peg by abutting against the end wall of the housing where the entrance of the peg attaching slot opens, is provided closer to the base end of the peg than a press-fitted portion of the peg that is press-fitted into the peg attaching slot.