An on-board device includes: an air-conditioning unit configured to perform air conditioning by blowing air-conditioning air into a vehicle cabin from an at outlet port that faces the vehicle cabin, and perform, in accordance with remote control, pre-air conditioning for air-conditioning the vehicle cabin before an occupant gets into a vehicle; a seat moving unit configured to move a vehicular seat in a seat front-rear direction, the vehicular seat being disposed such that a front face of a seat back faces the air outlet port; and a control unit configured to, when the remote control is perforated for performing the pre-air conditioning, control the air-conditioning unit such that the pre-air conditioning is performed, and control the seat moving unit such that the vehicular seat moves to a seat front side.