A rear door system for transferring hot cell equipment into or out of a hot cell is disclosed. The rear door system of the present invention includes a rear door, which is provided to a rear wall of the hot cell so as to be movable to open or close the rear wall of the hot cell, and a vertical moving table, which is provided at a predetermined position on the lower portion of the front surface of the rear door so as to be movable upwards or downwards. The rear door system further includes a drive unit, which is provided at a predetermined position in the lower end of the rear door to move the rear door, and a stationary working table, which is disposed above the vertical moving table and is fixed in the hot cell in a horizontal orientation. The rear door system further includes a removable table, which is removably coupled at a predetermined position to the stationary working table, and a hot cell crane hook and a service area crane hook, which are respectively provided inside and outside the hot cell.