To provide a liquid-feeder capable of controlling the consumption state and/or supplying state of the liquid by using an electric pressure gauge.

This liquid-feeder is constituted by a liquid storage device for storing a desired liquid, a liquid consumption device for consuming the liquid, a consumption device passage joining the liquid storage device with liquid consumption device and capable of feeding the liquid to the liquid consumption device, the electric pressure gauge and a hermetically sealed space joining the consumption device passage with the electric pressure gauge, and includes a pressure gauge passage capable of isolating the electric pressure gauge from the liquid, by the existence of a gas.