An infusion set (1) includes: a first flow path (10a) having a first connector (11a) and a downstream connector (19)； a first open/close valve (12a), a first liquid surface sensor (13a), a second liquid surface sensor (13b), a drip chamber (14), and a variable valve (17) that are provided in this order on the first flow path from the first connector side toward the downstream connector side； a droplet sensor (15) with which the drip chamber is provided； a second flow path (10b) having a second connector (11b)； and a second open/close valve (12b) provided on the second flow path. The second flow path is in communication with a portion of the first flow path between the first liquid surface sensor and the second liquid surface sensor. The controller is configured to control the first and second open/close valves and the variable valves based on signals from the first and second liquid surface sensors and the droplet sensor.
