The invention relates to an automatic assembling machine for a connector. A rack is provided with a rubber core conveying device and a shell conveying groove; a shell feeding device is arranged on theupper portion of the shell conveying groove, a shell material feeding device is matched with the right side of the shell conveying groove, and a rubber core ejecting-in port is formed in the front side of the shell conveying groove and is matched with a rubber core ejecting-in device; the shell material feeding device is connected with a shell vibration material feeding disk through a shell material feeding groove; the shell feeding device comprises a shell feeding lifting cylinder which is connected with a shell reciprocating feeding pull rod; the shell reciprocating feeding pull rod is connected with a shell feeding block; and feeding grooves matched with the left and right length of the shell are uniformly formed in the lower portion of the shell feeding block. According to the automatic assembling machine for the connector, by means of the shell feeding device in fixed distance feeding guarantees the fixed distance feeding of a shell, the fixed rubber core ejecting-in port is formed in the shell conveying groove, it is guaranteed that a rubber core is accurately ejected in from the rubber core ejecting-in port, automatic assembling of the connector rubber core and the shell isachieved, meanwhile the positioning and assembling structure is simplified, and the work efficiency is improved.