The submarine phenomenon can be prevented and the accuracy of a passenger's weight measurement is improved.A vehicle seat 1 comprises a pair of fixed lower rails 3 fixed on the floor of a passenger compartment, a pair of movable upper rails 4 which are engaged with the fixed lower rails 3 so as to be slidable in a front-and-rear direction with respect to each of the fixed lower rails 3, a sub frame 110 which is disposed at an upper side of the movable upper rails 4, load sensors 50, 60, 70, and 80 which lie between the sub frame 110 and the movable upper rails 4, brackets 8 and 9 which are disposed so as to erect them on each of the movable upper rails 4, and a submarine pipe 11 which is crossed between the brackets 8 and 9. The submarine pipe 11 is disposed to be slidable in a left-and-right direction with respect to the right bracket 9.