The object of the present invention is to provide a remote assistant system for a foundry, i.e., a plant that comprises a plurality of machines. The remote assistant system in a foundry includes a first sequencer for controlling a molding line and a second sequencer for controlling a molding machine. It further includes a sequencer-communicating mechanism for connecting the first sequencer to the second sequencer, a first mobile computer for transmitting information by video images, etc. to a remote location, a mechanism for providing communication between mobile computers to selectively connect one of the sequencers to the first mobile computer, a second mobile computer for receiving the information from the first mobile computer, for displaying the information, and for correcting the ladder logic program and giving instructions to the operator by an assistant at a remote location.