Rovers,such as MER and MSL,are sent to Mars and the geology search for the surface is performed by JPL /NASA[1]. MER and MSL are large- sized R overs and have the communication system which can perform direct communication with ground stations on the earth. R over needs to consist of Mars sample return missions currently assumed by this research very lightweight. In this case,the direct communication with the earth of the small rover is difficult. Therefore,communication of rover cannot but serve as a communication system through a lander. Moreover,since it is the opportunity of precious sample extraction,it is necessary to extract the topsoil of various places,and the sample of rock efficiently. Then,it is inquiring about the exploration system using two or more lightweight rovers. This study is about a method of a path planning for a robot( rover)exploration to somehowthe robot can get to the target place,facing fewer problems and also about a way of transmission for do not have a loss of communication due to obstacles. We assume a robot has a transmission device and ensure the communication transmissibility by putting it in the prescribed place on the path. In the path planning,candidate paths including the transmission device position by R R Tare generated and path optimization is carried out by evaluation function. In the simulation,the path taking account of communication transmissibility is planned with using transmission device. The proposed path planning method is confirmed by simulation. Rovers, such as MER and MSL, are sent to Mars and the geology search for the surface is performed by JPL / NASA [1]. MER and MSL are large- sized R overs and have the communication system which can perform direct communication with ground stations on the earth. R over needs to consist of Mars sample return offers prelude by this research very lightweight. In this case, the direct communication with the earth of the small rover is difficult. Therefore, communication of rover can not but serve as a communication system through a lander. Moreover, since it is the opportunity of precious sample extraction, it is necessary to extract the topsoil of various places, and the sample of rock efficiently. Then, it is in is about to explore the exploration system using two or more lightweight rovers. This study is about a method of a robot (rover) exploration to somehowthe robot can get to the target place, facing fewer problems and also about about a transmission of do not have a lo ss of communication due to obstacles. We assume a robot has a transmission device and ensure the communication transmissibility by putting it in the prescribed place on the path. In the path planning, candidate paths including the transmission device position by RR Tare generated and path optimization is carried out by evaluation function. In the simulation, the path taking account of communication transmissibility is planned with using transmission device. The proposed path planning method is confirmed by simulation.