Seat suspension mechanism

A seat suspension mechanism disposed between a vehicle body structure and a seat, the seat suspension mechanism comprising:

• a base frame attached on a vehicle body structure side;
• a seat support frame attached on a seat side;
• an intermediate frame located between the base frame and the seat support frame;
• a first link mechanism supporting the intermediate frame with respect to the base frame;
• a second link mechanism supporting the seat support frame with respect to the intermediate frame;
• an up-down direction spring mechanism which elastically biases the intermediate frame with respect to the base frame;
• and
• a first damper suspended between the base frame and the intermediate frame,
• the first link mechanism and the second link mechanism being provided in a positional relationship in which straight lines connecting connection center points of links connecting the intermediate frame and the seat support frame in the second link mechanism are closer to a vertical to a front-rear direction of a vehicle body at a balanced point than straight lines connecting connection center points of links connecting the base frame and the intermediate frame in the first link mechanism, and
• a front-rear direction spring mechanism which exhibits elastic force in accordance with movement of the links of the second link mechanism being provided.