An apparatus for calming a baby in an interior of a vehicle has a heartbeat sensor device (11, 12, 13) configured to capture a heartbeat input signal that depends on the heartbeat of an occupant in an interior (18) of a vehicle (10). A heartbeat signal processing device (14) is configured to produce a heartbeat output signal that depends on the heartbeat input signal. A calming signal output device (15, 16, 17) is configured to output a calming signal that depends on the heartbeat output signal and that is perceivable by a baby in the interior (19) of the vehicle (10). The apparatus is to configured to output the calming signal, at least intermittently, directly during the capture of the heartbeat input signal.