A base (41) includes a plurality of flow channels (33, 34) and detection sections (531, 541) for detecting the flow volumes of fluids flowing in the flow channels (33, 34). In the base (41), a blocking section (57) for blocking heat conduction between the flow channels (33, 34) is provided between the flow channels (33, 34). The blocking section (57) is configured of groove (58) formed in the base (41).
