A first pressure-sensitive switch group of a seating sensor includes first pressure-sensitive switches (SW11 to SW13) and second pressure-sensitive switches (SW21 to SW23) located on one side of a seat in a left-right direction from the first pressure-sensitive switches, and includes a first pressure-sensitive switch pair including the first pressure-sensitive switch (SW11) and the second pressure-sensitive switch (SW21), and the first pressure-sensitive switch (SW13) and the second pressure-sensitive switch (SW22) located between the first pressure-sensitive switch (SW11) and the second pressure-sensitive switch (SW21), a second pressure-sensitive switch pair including the first pressure-sensitive switch (SW12) and the second pressure-sensitive switch (SW22), and a third pressure-sensitive switch pair including the first pressure-sensitive switch (SW13) and the second pressure-sensitive switch (SW23), in which seating is detected when both the first pressure-sensitive switch and the second pressure-sensitive switch in at least one of the first to third pressure-sensitive switch pairs are turned on.