There has been a demand for an aspiration catheter which has a sufficient amount of aspiration, which is sufficiently flexible to satisfactorily track tortuous blood vessels, in which the possibility of kinking of a catheter shaft is decreased when the aspiration catheter is inserted into a guiding catheter from outside of the body, and in which good operationality is achieved. An aspiration catheter of the present invention includes an aspiration lumen for removing a substance by aspiration, the aspiration lumen extending to a hub provided at the proximal end of the catheter and a detachable core wire disposed in the aspiration lumen.