To provide a clamping device that is always capable of clamping a flexible tube in a good manner and assuredly closing the flexible tube without a large clamping force. A clamping device includes a holding member (7) that is capable of holding a flexible tube in which a fluid is allowed to flow, and a clamping member (8) that is capable of clamping and closing, as intended, a clamping portion (L5c) of the flexible tube that is held by the holding member. The clamping device further includes a heating device (12) that is capable of heating the clamping portion (L5c) of the flexible tube.
