A refrigerating and freezing device, comprising: a cabinet, wherein at least one storage compartment is defined therein, and a heating cavity configured to contain a to-be-processed object is defined in one of the storage compartments; and an electromagnetic heating device, configured to supply electromagnetic waves into the heating cavity so as to heat the to-be-processed object in the heating cavity, wherein the electromagnetic heating device is provided with an electromagnetic generation module configured to produce an electromagnetic wave signal and a power supply module configured to supply a power source to the electromagnetic generation module, wherein a power supply box is provided above a top of the cabinet, and heat dissipation holes configured to achieve communication between the interior of the power supply box and an external environment where the power supply box is located are provided in a box body of the power supply box; and the power supply module is disposed in the power supply box, a heat dissipation fan is further provided in the power supply box and is configured to drive airflow to flow between the interior of the power supply box and the external environment where the power supply box is located through the heat dissipation holes, so as to dissipate heat from the power supply module, wherein the power supply box comprises a lower bottom shell disposed on a top surface of the cabinet and an upper box body covering a top of the lower bottom shell; and the power supply module and the heat dissipation fan are both disposed on the lower bottom shell, characterized in that the upper box body comprises a top wall and a peripheral wall extending downwards from a periphery of the top wall; and the heat dissipation holes comprise a plurality of air inlet holes provided in a first side wall of the peripheral wall and a plurality of air outlet holes provided in a second side wall of the peripheral wall opposite to the first side wall, so as to allow the airflow driven by the heat dissipation fan to enter the power supply box through the air inlet holes and flow out through the air outlet holes, and thus forced convection heat dissipation is carried out on the power supply module. a cabinet, wherein at least one storage compartment is defined therein, and a heating cavity configured to contain a to-be-processed object is defined in one of the storage compartments; and an electromagnetic heating device, configured to supply electromagnetic waves into the heating cavity so as to heat the to-be-processed object in the heating cavity, wherein the electromagnetic heating device is provided with an electromagnetic generation module configured to produce an electromagnetic wave signal and a power supply module configured to supply a power source to the electromagnetic generation module, wherein a power supply box is provided above a top of the cabinet, and heat dissipation holes configured to achieve communication between the interior of the power supply box and an external environment where the power supply box is located are provided in a box body of the power supply box; and the power supply module is disposed in the power supply box, a heat dissipation fan is further provided in the power supply box and is configured to drive airflow to flow between the interior of the power supply box and the external environment where the power supply box is located through the heat dissipation holes, so as to dissipate heat from the power supply module, wherein the power supply box comprises a lower bottom shell disposed on a top surface of the cabinet and an upper box body covering a top of the lower bottom shell; and the power supply module and the heat dissipation fan are both disposed on the lower bottom shell, characterized in that the upper box body comprises a top wall and a peripheral wall extending downwards from a periphery of the top wall; and the heat dissipation holes comprise a plurality of air inlet holes provided in a first side wall of the peripheral wall and a plurality of air outlet holes provided in a second side wall of the peripheral wall opposite to the first side wall, so as to allow the airflow driven by the heat dissipation fan to enter the power supply box through the air inlet holes and flow out through the air outlet holes, and thus forced convection heat dissipation is carried out on the power supply module.