To provide a throttle valve device having a simple structure, can be manufactured at low cost, and having high silentness.

The throttle valve device (1) includes a valve seat member (10) formed with a valve sheet part (10a) and a valve body (20) which is in or out of contact with the valve sheet part (10a), wherein a fluid channel (30A) is formed along which the fluid passes between the valve seat member (10) and the valve body (20) while the valve body (20) is abutted on the valve sheet part (10a), between the valve seat member (10) and the valve body (20), and a cross-section reducing part is formed in which a cross-sectional area is successively decreasing toward the downstream from the upstream in at least a part of the fluid channel (30A).