A press-fit assembling device is provided to assemble enclosures including a chassis and a housing. The press-fit assembling device includes a base and a driver. The base includes a platform defined with a locating channel to secure the chassis located thereon. The driver is pivotally connected to one end of the base and is formed with a press plate. The press plate moves down under the control of the driver to press fit the housing and the chassis located on the platform. A plurality of stop blocks is arranged on the platform, and is used to prevent damage to the enclosure. The driver is also formed with a linkage set. When the press plate is lifted up, an aft part of the linkage set abuts against a cross rod and keeps the press plate from dropping down while the operator positions the chassis and housing for press-fitting.