An oven comprising: a casing having at least one air intake hole and an ejection hole through which air is discharged to the outside; a cooking chamber inside the casing and having an opening; a door that is arranged to open/close the opening and which forms a flow path for air inside the door using a plurality of sheets of glass (31, 32, 33) including inner glass for sealing the cooking chamber; a cooling fan arranged at an outer side of the cooking chamber so as to cool the door by drawing external air through the air intake hole; a cooling flow path arranged so that air drawn in by the cooling fan is capable of flowing towards the door in a first direction, so as to generate a flow of air inside the door; at least one door flow path (60, 70) that is arranged so that air drawn in at an end portion of the door is capable of passing through the door and flowing towards the other end portion adjacent to the cooling flow path; a cooling guide that is installed at the cooling flow path adjacent to the at least one door flow path and comprises a first end portion that is arranged to narrow the width of the cooling flow path; wherein the first end portion of the cooling guide is disposed to the rear of the door flow path formed by the inner glass so as to prevent a flow of air that passes through the door flow path from being disturbed; characterized in that the oven further comprises: an air guide adjacent to the ejection hole and arranged to change the direction of air driven by the cooling fan so that high temperature vapour from the cooking chamber is capable of being diffused downwards; a sensor installed to detect opening/closing of the door; and a movement unit that contacts the air guide, wherein the movement unit moves upwards and downwards according to the signal of the sensor and causes the air guide to be moved. a casing having at least one air intake hole and an ejection hole through which air is discharged to the outside; a cooking chamber inside the casing and having an opening; a door that is arranged to open/close the opening and which forms a flow path for air inside the door using a plurality of sheets of glass (31, 32, 33) including inner glass for sealing the cooking chamber; a cooling fan arranged at an outer side of the cooking chamber so as to cool the door by drawing external air through the air intake hole; a cooling flow path arranged so that air drawn in by the cooling fan is capable of flowing towards the door in a first direction, so as to generate a flow of air inside the door; at least one door flow path (60, 70) that is arranged so that air drawn in at an end portion of the door is capable of passing through the door and flowing towards the other end portion adjacent to the cooling flow path; a cooling guide that is installed at the cooling flow path adjacent to the at least one door flow path and comprises a first end portion that is arranged to narrow the width of the cooling flow path; an air guide adjacent to the ejection hole and arranged to change the direction of air driven by the cooling fan so that high temperature vapour from the cooking chamber is capable of being diffused downwards; a sensor installed to detect opening/closing of the door; and a movement unit that contacts the air guide, wherein the movement unit moves upwards and downwards according to the signal of the sensor and causes the air guide to be moved.