Flow channel structure and lock-up device

A flow channel structure configured to form a first flow channel which makes a first fluid chamber and a second fluid chamber communicate with each other therethrough, the flow channel structure comprising:

• a first plate including a first through hole, the first through hole penetrating the first plate in a thickness direction so as to open to the first fluid chamber;
• a second plate including a second through hole, the second through hole penetrating the second plate in the thickness direction so as to open to the second fluid chamber;
• and
• a third plate disposed between the first and second plates, the third plate including a first connecting through hole, the first connecting through hole penetrating the third plate in the thickness direction, the first connecting through hole larger in flow channel area than each of the first and second through holes, wherein
• the first and second through holes are disposed in different positions from each other as seen in the thickness direction, and
• the first connecting through hole communicates with the first and second through holes.