To provide an economical and highly reliable automatic assembling device capable of assembling with favorable precision and at high speed.

This automatic assembling device automatically assembles assembly parts such as frames with assembly base parts such as drawer lid main bodies by fasteners such as screws by means of fastening jigs. It is provided with a fixing device to fix the assembly base part to a prescribed position in the assembling device, an image processing device to compare the position of the assembly base part fixed by the fixing device with a preset position based on an image, and an installation device to correct the position of the fastening jig based on result of comparison by the image processing device to engage the fastener on the fastening jig corrected through a hole in the assembly part to an installation hole in the assembly base part for installing the assembly part to the assembly base part.