A coat drying device dries a coated film that is coated on a continuously transported coating object having first and second parts, where the second part has a greater heat capacity than the first part. The coat drying device includes a drying furnace, a hot air supply device and a control unit. The coating object is conveyed inside of the drying furnace main body. The hot air supply device heats the coating object by blowing hot air to the drying furnace. The control unit controls the hot air supply device based on a heat capacity of the coating object. The control unit controls the hot air supply device such that, when heating the second part, hot air with a greater amount of heat is supplied to the second part than an amount of heat in the hot air that is supplied to heat the first part.
