An intracardiac suture device comprises a first shaft assembly 1 including a first shaft 11 and a first suture needle-holding device 4 provided at a distal end of the first shaft 11; a second shaft assembly 2 comprising a second shaft 21; a third shaft assembly 3 comprising a third shaft 31 and a handling portion 33; and a puncture assembly 5 provided at a proximal end thereof with a second suture needle-holding device 51. The second shaft 21 is protrusible by sliding-movement from the distal end of the first shaft 11 toward the first suture needle-holding device 4, and a suture needle 6 is transferable between the first suture needle-holding device 4 and the second suture needle-holding device 51 when the third shaft 31 is slid to the distal end of the second shaft 21 after sliding the second shaft 21 to a position where a suture site is held between the second shaft 21 and the first suture needle-holding device 4.