A dishwasher comprising: a washing tub including a reserving unit configured to reserve wash water and containing therein an item to be washed; a water feed unit configured to feed water into the washing tub; a heating unit configured to heat the wash water reserved in the reserving unit; a temperature detecting unit configured to detect a temperature of the wash water reserved in the reserving unit; a washing unit including at least a washing pump for pressurizing the wash water and a washing nozzle for spraying the wash water toward the item to be washed; a water level detecting switch configured to detect a level of the wash water; and a control unit configured to: control the water feed unit, the heating unit, and the washing unit so as to carry out at least a wash water heating step being a step of heating the wash water without spraying the wash water through the washing nozzle, and a heating/rinsing step being a step of rinsing the item to be washed with heated wash water, which is carried out after the step of heating the wash water, wherein in the heating/rinsing step the wash water is heated while being sprayed toward the item to be washed, wherein the control unit is configured to control the heating unit and the washing unit based on the temperature detected by the temperature detecting unit, and to actuate the water feed unit to feed water to the washing tub until a water level is detected by the water level detecting switch; characterized in that the control unit is further configured to: estimate a thermal capacity of the heating unit in the wash water heating step, measure a time dt in the heating/rinsing step, wherein the time dt is a time duration from the time when the wash water has a first predetermined temperature until the wash water reaches a second predetermined temperature, estimate a volume of the item to be washed in consideration of the thermal capacity of heater and the time dt by comparing the rate of temperature rise of the wash water in the wash water heating step with the rate of temperature rise of the wash water in the heating/rising step, and control the heating unit and the washing unit based on the estimated volume of the item to be washed. a washing tub including a reserving unit configured to reserve wash water and containing therein an item to be washed; a water feed unit configured to feed water into the washing tub; a heating unit configured to heat the wash water reserved in the reserving unit; a temperature detecting unit configured to detect a temperature of the wash water reserved in the reserving unit; a washing unit including at least a washing pump for pressurizing the wash water and a washing nozzle for spraying the wash water toward the item to be washed; a water level detecting switch configured to detect a level of the wash water; and a control unit configured to: control the water feed unit, the heating unit, and the washing unit so as to carry out at least a wash water heating step being a step of heating the wash water without spraying the wash water through the washing nozzle, and a heating/rinsing step being a step of rinsing the item to be washed with heated wash water, which is carried out after the step of heating the wash water, wherein in the heating/rinsing step the wash water is heated while being sprayed toward the item to be washed, wherein the control unit is configured to control the heating unit and the washing unit based on the temperature detected by the temperature detecting unit, and to actuate the water feed unit to feed water to the washing tub until a water level is detected by the water level detecting switch; control the water feed unit, the heating unit, and the washing unit so as to carry out at least a wash water heating step being a step of heating the wash water without spraying the wash water through the washing nozzle, and a heating/rinsing step being a step of rinsing the item to be washed with heated wash water, which is carried out after the step of heating the wash water, wherein in the heating/rinsing step the wash water is heated while being sprayed toward the item to be washed, wherein the control unit is configured to control the heating unit and the washing unit based on the temperature detected by the temperature detecting unit, and to actuate the water feed unit to feed water to the washing tub until a water level is detected by the water level detecting switch; estimate a thermal capacity of the heating unit in the wash water heating step, measure a time dt in the heating/rinsing step, wherein the time dt is a time duration from the time when the wash water has a first predetermined temperature until the wash water reaches a second predetermined temperature, estimate a volume of the item to be washed in consideration of the thermal capacity of heater and the time dt by comparing the rate of temperature rise of the wash water in the wash water heating step with the rate of temperature rise of the wash water in the heating/rising step, and control the heating unit and the washing unit based on the estimated volume of the item to be washed.