A dishwasher comprising: a tub defining a washing space and accommodating dishes; and a heat pump apparatus configured to heat wash water introduced into the tub , wherein the heat pump apparatus comprises, a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor when the dishwasher performs a washing mode, the first heat exchanger configured to heat water introduced into the tub ; a first expansion valve to which refrigerant is introduced from the first heat exchanger when the dishwasher performs the washing mode, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; characterized in that the heat pump apparatus further comprises: a second expansion valve disposed in parallel with the first expansion valve , the second expansion valve to which refrigerant is introduced from the first heat exchanger when the dishwasher performs the washing mode; J Z a third heat exchanger disposed in parallel with the second heat exchanger , the third heat exchanger to which refrigerant is introduced from the second expansion valve when the dishwasher performs the washing mode; J Z and a four way valve connected with the compressor, the first heat exchanger , the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant. a tub defining a washing space and accommodating dishes; and a heat pump apparatus configured to heat wash water introduced into the tub , wherein the heat pump apparatus comprises, a compressor configured to compress refrigerant; a first heat exchanger to which refrigerant is introduced from the compressor when the dishwasher performs a washing mode, the first heat exchanger configured to heat water introduced into the tub ; a first expansion valve to which refrigerant is introduced from the first heat exchanger when the dishwasher performs the washing mode, the first expansion valve configured to expand refrigerant; a second heat exchanger to which refrigerant is introduced from the first expansion valve; characterized in that the heat pump apparatus further comprises: a second expansion valve disposed in parallel with the first expansion valve , the second expansion valve to which refrigerant is introduced from the first heat exchanger when the dishwasher performs the washing mode; J Z a third heat exchanger disposed in parallel with the second heat exchanger , the third heat exchanger to which refrigerant is introduced from the second expansion valve when the dishwasher performs the washing mode; J Z and a four way valve connected with the compressor, the first heat exchanger , the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant. a second expansion valve disposed in parallel with the first expansion valve , the second expansion valve to which refrigerant is introduced from the first heat exchanger when the dishwasher performs the washing mode; J Z a third heat exchanger disposed in parallel with the second heat exchanger , the third heat exchanger to which refrigerant is introduced from the second expansion valve when the dishwasher performs the washing mode; J Z and a four way valve connected with the compressor, the first heat exchanger , the second heat exchanger and the third heat exchanger and configured to change a flow path of a refrigerant. <EOS>