A refrigerator comprising: a main body; a storage chamber provided in the main body so that a front surface thereof is open; an internal door rotatably provided at a front surface of the main body so as to open and close the storage chamber and having an opening part in which a plurality of door guards are provided; an external door rotatably provided at a front surface of the internal door so as to open and close the opening part; and an internal door opening prevention device to allow or prevent opening of the internal door according to whether the external door is opened or closed, wherein the internal door opening prevention device comprises: a stopper coupled to a lower portion of the main body; a locking part rotatably coupled to a lower portion of the internal door and rotated according to whether the external door is opened or closed so as to be locked and unlocked with the stopper; a spring configured to elastically support the locking part; and a cover configured to cover the locking part so as to prevent the locking part from being exposed to an outside, the refrigerator being characterised in that the cover has a rotational protrusion to which the locking part is rotatably coupled, wherein the stopper and the cover are respectively coupled to the lower portion of the main body and the lower portion of the internal door by fastening members, and in that a protruding part is coupled to a lower portion of the external door so as to be in contact with the locking part and thus to rotate the locking part so as to be unlocked from the stopper when the external door is closed, thus compressing the spring with the locking part and storing a compressed force with the spring, whereas when the external door is opened, a release of the protruding part from the contact with the lower portion of the external door causes a rotation of the locking part owing to said compressed force of the spring, whereby the locking part may be locked with the stopper. a main body; a storage chamber provided in the main body so that a front surface thereof is open; an internal door rotatably provided at a front surface of the main body so as to open and close the storage chamber and having an opening part in which a plurality of door guards are provided; an external door rotatably provided at a front surface of the internal door so as to open and close the opening part; and an internal door opening prevention device to allow or prevent opening of the internal door according to whether the external door is opened or closed, wherein the internal door opening prevention device comprises: a stopper coupled to a lower portion of the main body; a locking part rotatably coupled to a lower portion of the internal door and rotated according to whether the external door is opened or closed so as to be locked and unlocked with the stopper; a spring configured to elastically support the locking part; and a cover configured to cover the locking part so as to prevent the locking part from being exposed to an outside, the refrigerator being characterised in that the cover has a rotational protrusion to which the locking part is rotatably coupled, wherein the stopper and the cover are respectively coupled to the lower portion of the main body and the lower portion of the internal door by fastening members, and in that a protruding part is coupled to a lower portion of the external door so as to be in contact with the locking part and thus to rotate the locking part so as to be unlocked from the stopper when the external door is closed, thus compressing the spring with the locking part and storing a compressed force with the spring, whereas when the external door is opened, a release of the protruding part from the contact with the lower portion of the external door causes a rotation of the locking part owing to said compressed force of the spring, whereby the locking part may be locked with the stopper. a stopper coupled to a lower portion of the main body; a locking part rotatably coupled to a lower portion of the internal door and rotated according to whether the external door is opened or closed so as to be locked and unlocked with the stopper; a spring configured to elastically support the locking part; and a cover configured to cover the locking part so as to prevent the locking part from being exposed to an outside, the refrigerator being characterised in that the cover has a rotational protrusion to which the locking part is rotatably coupled, wherein the stopper and the cover are respectively coupled to the lower portion of the main body and the lower portion of the internal door by fastening members, and in that a protruding part is coupled to a lower portion of the external door so as to be in contact with the locking part and thus to rotate the locking part so as to be unlocked from the stopper when the external door is closed, thus compressing the spring with the locking part and storing a compressed force with the spring, whereas when the external door is opened, a release of the protruding part from the contact with the lower portion of the external door causes a rotation of the locking part owing to said compressed force of the spring, whereby the locking part may be locked with the stopper.