PURPOSE: To improve sealing property between a combustion chamber and a liner outer circumferential part on the combustion chamber side of a cylinder liner, in relation to the cylinder structure of an internal combustion engine provided with the cylinder liner.

CONSTITUTION: A taper screw 2a is formed on the outer circumferential surface of an upper end part positioned on the combustion chamber 15 side of a cylinder liner 2, and also an O-ring 16 is provided in a mounting groove 2b in the lower part outer circumferential surface of the liner 2. On the other hand, a taper screw 1a screwed in the taper screw 2a is formed around the combustion chamber 15 of a monoblock 1, and also a supporting part 1b is formed below a water jacket 13. The taper screw 1a is screwed in the taper screw 2a with a prescribed torque, and the cylinder liner 2 is threadedly engaged with the monoblock 1 and fixed thereto. It is thus possible to improve sealing property between the combustion chamber 15 and the water jacket 13 regardless of the difference in thermal expansion between the block 1 and the liner 2 by screwing of the taper screws 1a, 2a which are provided on the combustion chamber 15 side.