The invention provides an automatic lubricant supplying device of an electric opening device for a weaving machine. The automatic lubricant supplying device includes an oil feeding pump, an oil feeding nozzle, an oil feeding pipe, and pipe supporting members. The oil feeding pump is fixedly mounted to the framework of the weaving machine at a corresponding position closer to the framework of the weaving machine than the corresponding bearing. The oil feeding nozzle is mounted to a corresponding connecting rod in order to direct the corresponding bearing and to connect to a corresponding oil feeding pipe. The pipe supporting members are fixed to the corresponding connecting rod. Each pipe supporting member enables the width of the pipe supporting members smaller than the width of the connecting rod and is provided with rigidity in the front-back direction of the weaving machine. The oil feeding pipe arranged at a position closer to the corresponding oil feeding nozzle is fixedly connected to the corresponding connecting rod, moreover, the oil feeding pipe arranged a position closer to the corresponding oil pump is fixedly connected to the corresponding pipe supporting member.