Tube joining device

A tube joining device that fuses an end of a first tube and an end of a second tube by a plate-shaped cutting member that is heated, and replaces the fused end of the first tube and the fused end of the second tube and joins the fused ends in an aseptic condition, comprising:

• a first tube holding portion that is capable of holding one tube between the first tube and the second tube;
• a second tube holding portion that is capable of holding the other tube between the first tube and the second tube;
• a tube superimposing portion that causes the first tube holding portion and the second tube holding portion to relatively approach each other to dispose the one tube and the other tube in a superimposed manner;
• and
• a switching mechanism that is capable of switching holding of the other tube by the second tube holding portion and release of the holding,
• wherein the switching mechanism applies a biasing force for maintaining a state in which the other tube is held to the second tube holding portion, and applies a biasing force for maintaining a state in which the holding of the other tube is released to the second tube holding portion in accordance with the relative approaching of the first tube holding portion and the second tube holding portion.