Provided is a sample injection device for flow-type analysis including a cylindrical needle (27) which penetrates through an upper wall and a lower wall of a sample injection portion (22) of a carrier-liquid channel through ring-like sealing members (25, 26). The needle (27) includes an inner hole (41) which is closed on a side of a lower end of the needle (27) and open on an outer peripheral surface as a horizontal hole (42). The needle moving unit (44) induces the needle (27) to move downward so that the horizontal hole (42) faces an inside of a sample vessel (40) to draw the sample to the inside of the needle (27). Then the moving unit (44) induces the needle (27) to move upward so that the horizontal hole (42) faces an inside of the sample injection portion (22) to inject the sample in the inside of the needle (27). At an intermediate position, washing liquid is discharged from the horizontal hole (42) of the needle (27), and the washing liquid is recovered via a discharge path (15).