A tube connecting apparatus capable of stably and reliably connecting tubes in which liquid is contained and sealed is provided. A tube connecting apparatus 1 equips a first tube-holding assembly 2 and a second tube-holding assembly 3, each holding tube 8, 9 in which blood is contained and sealed in a parallel state. A first clamp 6 and a second clamp 7, each pressing the tubes to a flat state, is provided at the first tube-holding assembly 2 and the second tube-holding assembly 3. A tube-pushing member 10 which presses the tubes to a flat state is disposed movably to and integrally with the first clamp 6 at a side of the second clamp 7. The tube connecting apparatus 1 has a cutting mechanism 4, disposed between the first clamp 6 and the second clamp 7, for melting and cutting the tubes, and has a movement mechanism which moves the first tube-holding assembly 2 and the second tube-holding assembly 3 such that end portions to be connected contact closely each other.