The flow rate detection device includes a sensor element and a support. The sensor element includes: a cavity which is formed in a rear surface of a plate-shaped semiconductor silicon substrate by removing part of the plate-shaped semiconductor silicon substrate; and a thin film portion which is disposed over the cavity and includes a detecting element. The support includes a fitting portion into which the sensor element is to be disposed. The sensor element is supported to the fitting portion by an adhesive in a floating manner. A gap formed between the sensor element and the fitting portion is filled with an anti-undercurrent material. The sensor element has a texture including protrusions and depressions formed on a surface opposed to the fitting portion, and the anti-undercurrent material is brought into contact with the texture.