[Problem] Provided are a catheter and a catheter device, in which a flushing liquid, air, or a residue of blood or the like is inhibited from flowing out into a blood vessel, and blood collecting and flushing can be performed in a low invasive manner. [Means for Resolution] A catheter device 1 includes an outer tube 211 which includes a first distal end opening portion 211h to be introduced into a living body and in which a first lumen 10a capable of circulating a fluid is formed； an inner tube 212 which is disposed in the first lumen, which includes a second distal end opening portion 212h positioned closer to the proximal side than the first distal end opening portion, and in which a second lumen 10b capable of circulating a fluid is formed； and an outflow/inflow inhibiting portion which is partitioned in the first lumen between the first distal end opening portion and the second distal end opening portion and inhibits a fluid from flowing out from the first lumen or a fluid from flowing into the first lumen via the first distal end opening portion, due to a perfusion of a fluid which is supplied to the first lumen and flows to the second lumen.
