A sample injection port 10 for injecting a sample into a chromatograph or other devices is composed of a body 13 made of an inelastic material, a first seal member 14 made of an elastic material and attached to one end of the body part 13, and a second seal member 15 made of an elastic material and attached to the other end of the body part 13. A first through hole formed in the first seal member 14, a second through hole formed in the second seal member 15 and a third through hole formed in the body part 13 are coaxially connected to form an introduction hole for sample injection. With this construction, a sample injection port which has a small inner diameter, is easy to manufacture, and yet capable of achieving a high pressure resistance can be provided.