Provided is a system for supplying a liquid (such as an irritative chemical solution) safely. This liquid supplying system comprises: (a) a means that creates a negative pressure in a treatment chamber by driving a first depressurizing means and depressurizing the treatment chamber； (b) a means that introduces the negative pressure of the treatment chamber to a measurement chamber； (c) a means that maintains the negative pressure introduced to the measurement chamber； (d) a means that sucks a liquid from a container into the measurement chamber by employing the negative pressure of the measurement chamber； and (e) a means that sucks the liquid of the measurement chamber into the treatment chamber by employing a vacuum in the treatment chamber.
