Fluid flow device and flow error detection method

A fluid flow device which causes a processing object fluid to flow, comprising:

• a channel forming body which forms a plurality of fluid channels that allow respective processing object fluids to flow through the fluid channels, a plurality of detection spaces corresponding to the plurality of fluid channels, each of the plurality of spaces extending in a longitudinal direction and having opposite ends with respect to the longitudinal direction, at least one of the opposite ends being sealed, and a plurality of communication channels each connected to a channel connection part that is set at each of the plurality of fluid channels and to a space connection part that is set in the detection space corresponding to the fluid channel to thereby provide communication between the channel connection part and the space connection part;
• and
• detection liquids and detection gases that are contained in the plurality of detection spaces, respectively, wherein:
• the channel forming body includes at least one plate layer, in which the plurality of fluid channels are arranged in one major surface of the plate layer, and the plurality of spaces are formed in the other major surface on an opposite side of the plate layer;
• each of the detection liquids and each of the detection gases are contained in the detection space so as to be aligned in the longitudinal direction of the detection space to form an interface between the detection liquid and the detection gas and so that a region where the detection liquid exists includes the space connection part;
• and
• the detection gas is contained in the detection space so as to allow a position of the interface to change with a pressure change of the processing object fluid at the channel connection part.