An oven comprising: a casing; a cooking compartment located inside the casing and having an open front; and a door assembly mounted to the cooking compartment to open and close the open front of the cooking compartment, wherein the door assembly has an inner space and the door assembly comprises: a rear plate and a front plate to form the inner space of the door assembly; a first inner plate installed in the inner space to divide the inner space; a shielding member located between the first inner plate and the rear plate of the door assembly to block air circulation in a fluid path formed between the first inner plate and the rear plate; and a side frame (103a, 103b) arranged on both lateral sides of the inner space formed between the front plate and the rear plate, wherein each lateral side frame (103a, 103b) includes a side flow-in unit (104a, 104b), each side flow-in unit (104a, 104b) comprising an opening extending along an outer side of the side frame (103a, 103b) that provides a passage for air from outside the door assembly to flow into the inner space through the side flow-in unit (104a, 104b) of the side frame, wherein the shielding member is formed to extend along the bottom and both sides of the first fluid path, to shield the bottom and both sides of the first fluid path in order to block air flowing into the inner space of the door assembly from an open bottom of the door assembly or through the side flow-in unit from moving into the fluid path. a casing; a cooking compartment located inside the casing and having an open front; and a door assembly mounted to the cooking compartment to open and close the open front of the cooking compartment, wherein the door assembly has an inner space and the door assembly comprises: a rear plate and a front plate to form the inner space of the door assembly; a first inner plate installed in the inner space to divide the inner space; a shielding member located between the first inner plate and the rear plate of the door assembly to block air circulation in a fluid path formed between the first inner plate and the rear plate; and a side frame (103a, 103b) arranged on both lateral sides of the inner space formed between the front plate and the rear plate, wherein each lateral side frame (103a, 103b) includes a side flow-in unit (104a, 104b), each side flow-in unit (104a, 104b) comprising an opening extending along an outer side of the side frame (103a, 103b) that provides a passage for air from outside the door assembly to flow into the inner space through the side flow-in unit (104a, 104b) of the side frame, wherein the shielding member is formed to extend along the bottom and both sides of the first fluid path, to shield the bottom and both sides of the first fluid path in order to block air flowing into the inner space of the door assembly from an open bottom of the door assembly or through the side flow-in unit from moving into the fluid path. a rear plate and a front plate to form the inner space of the door assembly; a first inner plate installed in the inner space to divide the inner space; a shielding member located between the first inner plate and the rear plate of the door assembly to block air circulation in a fluid path formed between the first inner plate and the rear plate; and a side frame (103a, 103b) arranged on both lateral sides of the inner space formed between the front plate and the rear plate, wherein each lateral side frame (103a, 103b) includes a side flow-in unit (104a, 104b), each side flow-in unit (104a, 104b) comprising an opening extending along an outer side of the side frame (103a, 103b) that provides a passage for air from outside the door assembly to flow into the inner space through the side flow-in unit (104a, 104b) of the side frame, wherein the shielding member is formed to extend along the bottom and both sides of the first fluid path, to shield the bottom and both sides of the first fluid path in order to block air flowing into the inner space of the door assembly from an open bottom of the door assembly or through the side flow-in unit from moving into the fluid path.