A load detection sensor unit 1A includes: a load detection sensor 5 that has a sensor sheet 50 having a pair of resinous insulating sheets 56s and 57s, a first electrode 56e provided on a surface of one insulating sheet 56s, and a second electrode 57e forming a pair with the first electrode 56e, and a metal plate 60 provided in at least a portion overlapping with the first electrode 56e and the second electrode 57e on one surface of the sensor sheet 50; and a pressing member 4 that has a pressing portion 46 disposed on the side of the metal plate 60 opposite to the side of the sensor sheet 50 and pressing the metal plate 60. The pressing portion 46 is harder than the seat cushion SC and the sensor sheet 50 and the metal plate 60 are bonded by an adhesive layer 70.