To provide a heating device of an emulsion tank in an asphalt emulsion spraying device capable of preventing an asphalt emulsion from being deteriorated and providing good flowability to the emulsion by uniformly and efficiently heating the emulsion in an emulsion tank mounted on an asphalt emulsion spraying vehicle.

A jacket 2 in which a hot water chamber 3 is formed is attached to the lower outer peripheral surface of the emulsion tank 1. A hot water heated to a specified temperature is introduced into the hot water chamber 3 from the one end by a heating means. With the inside of the hot water tank 3 filled with the hot water, the hot water is forced to flow and guided from the other end of the hot water chamber 3 to the outside and re-guided into the hot water chamber 3. Also, the hot water chamber 3 is partitioned into a plurality of compartments 3a-3f by partition plates 4a-4e, and the hot water is forced to so flow to the other end as to bypass in the vertical direction through the partition plates for uniformly heating the emulsion tank 1.