Abstract: An occupant detection method includes detecting a load acting on a seat for a vehicle with use of a load sensor provided at the seat, monitoring a seating sensor output outputted from a seating sensor forming a detection region at the seat, and determining that a child occupant is seated at a child restraint seat installed at the seat when a detection value of the load sensor is equal to or larger than a minimum value determining that an adult occupant is seated at the seat and equal to or smaller than a maximum value determining that the child occupant is seated at the child restraint seat, in a case where the seating sensor output indicates a state in which a seating load of an occupant is not applied to the detection region, the seating load corresponding to a load of the occupant while the occupant is seated.

Abstract: An occupant sensing method includes steps of: sensing installation of a child seat on a seat of a vehicle; storing a detection value of a load sensor which is provided to be attached to the seat and detects an input load as a first load value, when the installation of the child seat is sensed; storing a detection value of the load sensor as a second load value when a predetermined time period has elapsed from a time point at which the installation of the child seat is sensed; and estimating a load change amount at the time of getting on/off which is a change amount of a load that is generated as the occupant gets on/off the child seat, based on a difference value between the first load value and the second load value.