A press-fitting device in which a terminal of a connector having a staggered arrangement section of the terminal of the connector is press-fitted into an insertion hole is provided. In the press-fitting device, a first terminal restricting member on which a guide section for restricting a vertical displacement of the terminals between the terminals along the lateral direction of the connector housing and a second terminal restricting member on which a guide section for restricting the lateral displacement of the terminals between the terminals along the vertical direction of the connector housing in an upper or lower part of the first terminal restricting member are provided. A guide groove to which terminals on an interior side of the connector housing are introduced is provided at a tip end portion of the guide portion positioned at the staggered arrangement section of the terminals.