To provide a flow controlling device capable of providing an accurate flow set by a setting device without mutual interference between flow controlling devices. A flow controlling device having a solenoid valve for adjusting the opening of a flow path and a valve driving circuit for driving the valve, having an analog inputting circuit for converting an inputted analog voltage value or analog electric current value into a specific digital value or analog value and then transmitting; a controlling portion processing the digital value or analog value transmitted from the inputting circuit and outputting an instruction signal depending on the flow that has been set; a signal transmitting portion that electrically isolates the controlling portion and the valve driving circuit and sends, to the valve driving circuit, the instruction signal from the controlling portion; an isolating power supply circuit for electrically isolating the analog inputting circuit and the controlling portion and for supplying a power supply to the analog inputting circuit and the controlling portion; and a non-isolating power supply circuit for providing a power supply to the valve driving circuit.