Vehicle seat

A vehicle seat, comprising:

• a seat cushion that supports buttock portions and thigh portions of a passenger having a physique corresponding to AM50;
• and
• a backrest, that supports a back portion of the passenger,
• wherein at the backrest, resistance to relative displacement of the passenger in a left-right direction is larger at both left-right direction side portions of a front surface of an upper portion than at a left-right direction central portion thereof,
• wherein the seat cushion has:
• left and right side reinforcing portions that reinforce portions of a cushion pad at left-right direction outer sides, and at obliquely lower sides with respect to front-rear direction central portions of the thigh portions of the passenger, the front-rear direction central portions of the thigh portions of the passenger being regions that are within a range of 60 mm or more in the front-rear direction and have centers that are 60% of a distance from a trochanter of the passenger to a side of a knee of the passenger, given that a distance between the trochanter and an area behind the knee, which is obtained by subtracting a distance between the seated buttock portions and the trochanter from a distance between the seated buttock portions and the area behind the knee, which distances are prescribed by a database of dimensions of human bodies, is considered to be the entire distance from the trochanter to the side of the knee, and
• left and tight lower surface reinforcing portions that reinforce portions of a lower surface of the cushion pad at left-right direction outer sides, and at obliquely lower sides with respect to the buttock portions of the passenger,
• wherein left and right back side supporting portions are provided at both left-right direction side portions of the backrest, the left and right back side supporting portions projecting outward toward a front side of the backrest at a location that is closer to a lower portion of a chest portion of the passenger than an upper portion of the chest portion of the passenger and at a height corresponding at least to the lower portion of the chest portion of the passenger, the lower portion of the chest portion corresponding to a seventh and eighth rib of the passenger having the physique corresponding to AM50 when seated, a width between the left and tight back side supporting portions at the height corresponding to a range from 115% to 125% of a width dimension of the lower portion of the chest portion of the passenger.