A preform heating apparatus has cover members 164 provided to close upper parts of two transport lines arranged in parallel, heating units 162 each having heaters 166 for heating preforms 200, and a first supply section for supplying cooling air into the cover members 164. The heating units 162 are each provided within each cover member 164 on a side between the transport lines. The first supply section introduces cooling air from air delivery spaces 169 provided between the transport lines into the cover members 164 through gaps between the heaters 166 to supply the cooling air toward the preforms 200.