To provide a liquid heating device capable of efficiently heating supplied liquid while preventing the damage of the device.

The liquid heating device 1 is provided with a first heater part 7 provided upstream in a passage formed of liquid L supplied into a heating pipe 2, and a second heater part 8 provided downstream, and heats the liquid L in the heating pipe 2 by heating parts 7b, 8b which the heater parts 7, 8 have. The heater parts 7, 8 have the heating parts 7b, 8b formed by sealing carbon wire heating elements 13 in glass tubes 10a, and glass tubes 10b with a diameter larger than the glass tubes 10a of the heating parts 7b, 8b, and comprise terminal parts 7a, 8a supporting the heating parts 7b, 8b into the heating pipe 2. In at least the second heater part 8, a predetermined portion of the glass tube 10b which the terminal part 8a has is disposed in the liquid L supplied into the heating pipe 2, together with the glass tube 10b of the heating part 8b.