A vehicular detector configured to transmit and receive a radio signal with a reader provided in a vehicle , detect seating of an occupant on a seat in the vehicle , and transmit a detection signal, the vehicular detector comprising: a first flexible sheet ; a second flexible sheet placed opposite to the first flexible sheet ; and an insulation sheet having electrical insulating property and intervening between the first flexible sheet and the second flexible sheet , characterized in that the first flexible sheet includes an antenna unit formed on a surface as a conductive pattern and configured to receive a transmission signal including a power supply radio signal from the reader , and a first contact portion electrically connected to the antenna unit and formed on a first opposing surface facing the second flexible sheet , the second flexible sheet includes a controller formed on a surface as a conductive pattern and configured to be driven by the transmission signal received by the antenna unit and output the detection signal, and a second contact portion electrically connected to the controller and formed on a second opposing surface facing the first flexible sheet , the insulation sheet has a through hole that, at a position where the first contact portion and the second contact portion face, runs through from the first opposing surface to the second opposing surface , and the first contact portion and the second contact portion become a state of making contact with each other by an external force based on seating of the occupant, cause the antenna unit to output the transmission signal to the controller , and cause the controller to output the detection signal to the antenna unit . a first flexible sheet ; a second flexible sheet placed opposite to the first flexible sheet ; and an insulation sheet having electrical insulating property and intervening between the first flexible sheet and the second flexible sheet , characterized in that the first flexible sheet includes an antenna unit formed on a surface as a conductive pattern and configured to receive a transmission signal including a power supply radio signal from the reader , and a first contact portion electrically connected to the antenna unit and formed on a first opposing surface facing the second flexible sheet , an antenna unit formed on a surface as a conductive pattern and configured to receive a transmission signal including a power supply radio signal from the reader , and a first contact portion electrically connected to the antenna unit and formed on a first opposing surface facing the second flexible sheet , the second flexible sheet includes a controller formed on a surface as a conductive pattern and configured to be driven by the transmission signal received by the antenna unit and output the detection signal, and a second contact portion electrically connected to the controller and formed on a second opposing surface facing the first flexible sheet , a controller formed on a surface as a conductive pattern and configured to be driven by the transmission signal received by the antenna unit and output the detection signal, and a second contact portion electrically connected to the controller and formed on a second opposing surface facing the first flexible sheet , the insulation sheet has a through hole that, at a position where the first contact portion and the second contact portion face, runs through from the first opposing surface to the second opposing surface , and the first contact portion and the second contact portion become a state of making contact with each other by an external force based on seating of the occupant, cause the antenna unit to output the transmission signal to the controller , and cause the controller to output the detection signal to the antenna unit . <EOS>