A sheet heater includes a first conveyance belt configured to convey a sheet on which a liquid has been discharged in a conveyance direction, a heating unit facing the first conveyance belt, the heating unit configured to heat the sheet conveyed by the first conveyance belt, and a second conveyance belt disposed upstream of the first conveyance belt in the conveyance direction, the second conveyance belt configured to convey the sheet to the first conveyance belt. A surface temperature of the second conveyance belt is lower than a surface temperature of the first conveyance belt when the first conveyance belt and the second conveyance belt convey the sheet.