An in-vehicle heating device according to the present invention is provided on a lower part of a front side of a seat cushion (31) serving as a seating unit of a vehicle seat (30). The in-vehicle heating device includes: an air feeder (11) including a suction opening (11a) through which external air is sucked into the air feeder (11); a warm air generator (12) including a heater (22) therein, the warm air generator (12) being configured to heat air fed from the air feeder (11) to generate warm air; and a blow-out unit configured to blow out the warm air from the warm air generator (12), such that the warm air is blown out forward of the seat cushion (31). At least a part of the blow-out unit is positioned at a front of the seat cushion (31), and doubles as a front shield, which serves as a decorative member.