An oven for performing a heat stage for implementing air sous vide, the oven comprising: a case in which a cooking chamber is formed; a sensor configured to sense a temperature of the cooking chamber; a convection module comprising a convection heater configured to heat air and a convection fan configured to supply the air heated by the convection heater into the cooking chamber; and a controller configured to control the convection module, wherein the heat stage comprises a first heat stage and a second heat stage that are sequentially performed, wherein the cooking chamber is configured to receive a cooking ingredient before the first heat stage, wherein the controller is configured to control the convection module for each preset cycle in each of the first and second heat stages, and wherein, in each cycle of the second heat stage, the controller is configured to: turn on the convection heater at the start time of each cycle, and control the turn-on and turn-off of the convection heater from a first time point that arrives after the start of each cycle, based on a comparison result of a hysteresis curve having a predetermined target temperature as a set value with the sensed temperature, whereby each cycle of the second heat stage comprises a first sub-cycle and a second sub-cycle, in the first sub-cycle, the controller turns on the convection heater for a preset time period and turn off the convection heater for the other time period, characterized in that, in the second sub-cycle, the controller controls the turn-on and turn-off of the convection heater based on the hysteresis algorithm based on a hysteresis curve in the second sub-cycle. a case in which a cooking chamber is formed; a sensor configured to sense a temperature of the cooking chamber; a convection module comprising a convection heater configured to heat air and a convection fan configured to supply the air heated by the convection heater into the cooking chamber; and a controller configured to control the convection module, wherein the heat stage comprises a first heat stage and a second heat stage that are sequentially performed, wherein the cooking chamber is configured to receive a cooking ingredient before the first heat stage, wherein the controller is configured to control the convection module for each preset cycle in each of the first and second heat stages, and wherein, in each cycle of the second heat stage, the controller is configured to: turn on the convection heater at the start time of each cycle, and control the turn-on and turn-off of the convection heater from a first time point that arrives after the start of each cycle, based on a comparison result of a hysteresis curve having a predetermined target temperature as a set value with the sensed temperature, whereby each cycle of the second heat stage comprises a first sub-cycle and a second sub-cycle, in the first sub-cycle, the controller turns on the convection heater for a preset time period and turn off the convection heater for the other time period, characterized in that, in the second sub-cycle, the controller controls the turn-on and turn-off of the convection heater based on the hysteresis algorithm based on a hysteresis curve in the second sub-cycle. turn on the convection heater at the start time of each cycle, and control the turn-on and turn-off of the convection heater from a first time point that arrives after the start of each cycle, based on a comparison result of a hysteresis curve having a predetermined target temperature as a set value with the sensed temperature, whereby each cycle of the second heat stage comprises a first sub-cycle and a second sub-cycle, in the first sub-cycle, the controller turns on the convection heater for a preset time period and turn off the convection heater for the other time period, characterized in that, in the second sub-cycle, the controller controls the turn-on and turn-off of the convection heater based on the hysteresis algorithm based on a hysteresis curve in the second sub-cycle.