Dilute chemical solution production device

A dilute chemical solution production device that produces a dilute chemical solution of a second liquid by adding the second liquid to a first liquid, the dilute chemical solution production device comprising:

• a first pipe that flows the first liquid;
• an undiluted solution tank that stores the second liquid;
• a second pipe that connects the undiluted solution tank and the first pipe;
• a pump that adds the second liquid into the first pipe through the second pipe;
• a conductivity measuring meter provided on a downstream side of a connection site between the first pipe and the second pipe with respect to a flow direction of the first liquid;
• and
• a controller that controls the pump based on a measured value of the conductivity measuring meter,
• wherein the first pipe is provided with a first bent portion and a second bent portion, the first bent portion is disposed in a vicinity of the connection site with the second pipe, and the second bent portion is disposed between the first bent portion and the conductivity meter, and
• a distance between the first bent portion and the second bent portion is 20 to 50 cm.