Our research focuses on a user support system for the realisation of two aims; firstly, the consistent management and support of a definition procedure for a distributed simulation while storing and re-using definition parameters, and secondly, the remote execution of a distributed simulation system with a single manufacturing system designer. In this paper, we clarify the requirements of the user support system. We propose requirement functions and a fundamental structure of the user support system. We develop a user support system that is based on the use of the distributed simulation network system and the synchronisation method developed in the past research. The user support system is conformed using a case to evaluate a hypothetical manufacturing system in which motors are produced. With this manufacturing system, it is assumed that three separate companies design the manufacturing system concurrently and that each designer is located away from the other designers in Japan. It is also assumed that a designer from one of the three companies executes the distributed simulation system using the user support system. The case study was then carried out to evaluate the performance of the co-operative work.