A low temperature storage apparatus, comprising: a main body having a storage chamber; a door coupled to the main body and opening and closing the storage chamber; a tray (110,210) provided in a storage space within the main body and including a plurality of storage slots (130,230) having a concave shape and configured to respectively receive a plurality of articles to be stored; a light emitting device installed in the storage space so as to illuminate an inside of the storage chamber; a light sensing device comprising a plurality of illumination sensors (150,250) respectively arranged under the plurality of storage slots and configured to sense light incident upon the plurality of storage slots from the light emitting device, wherein a plurality of through holes (140,240) are respectively formed in bottom portions of the plurality of storage slots (130,230) and the plurality of illumination sensors (150,250) are arranged on a circuit board (160,260), at positions corresponding to the plurality of through holes (140,240); a cover plate (170,270) covering an upper surface of the circuit board and including a plurality of accommodation holes at which the plurality of illumination sensors (150,250) is respectively received; a base plate (180,280) attached to a lower surface of the circuit board; and a plurality of transparent lids (175,275) respectively received in the plurality of accomodation holes of the cover plate (170,270) so as to enclose the plurality of illumination sensors (150,250) in the plurality of accommodation holes; and a controller controlling the light emitting device, receiving sensing signals from the light sensing device, and providing state information related to the plurality of stored articles, wherein the controller is configured to: switch the light emitting device on when the door is opened; after the door is closed, sense whether or not a sensing signal received for each of the plurality of storage slots is changed from a previous sensing signal, and count storage time from a point at which the sensing signal is determined to have changed if the sensing signal is changed from stored article non-existence to stored article existence; and switch the light emitting device off when a predetermined time from a point at which the door is closed has elapsed. a main body having a storage chamber; a door coupled to the main body and opening and closing the storage chamber; a tray (110,210) provided in a storage space within the main body and including a plurality of storage slots (130,230) having a concave shape and configured to respectively receive a plurality of articles to be stored; a light emitting device installed in the storage space so as to illuminate an inside of the storage chamber; a light sensing device comprising a plurality of illumination sensors (150,250) respectively arranged under the plurality of storage slots and configured to sense light incident upon the plurality of storage slots from the light emitting device, wherein a plurality of through holes (140,240) are respectively formed in bottom portions of the plurality of storage slots (130,230) and the plurality of illumination sensors (150,250) are arranged on a circuit board (160,260), at positions corresponding to the plurality of through holes (140,240); a cover plate (170,270) covering an upper surface of the circuit board and including a plurality of accommodation holes at which the plurality of illumination sensors (150,250) is respectively received; a base plate (180,280) attached to a lower surface of the circuit board; and a plurality of transparent lids (175,275) respectively received in the plurality of accomodation holes of the cover plate (170,270) so as to enclose the plurality of illumination sensors (150,250) in the plurality of accommodation holes; and a controller controlling the light emitting device, receiving sensing signals from the light sensing device, and providing state information related to the plurality of stored articles, wherein the controller is configured to: switch the light emitting device on when the door is opened; after the door is closed, sense whether or not a sensing signal received for each of the plurality of storage slots is changed from a previous sensing signal, and count storage time from a point at which the sensing signal is determined to have changed if the sensing signal is changed from stored article non-existence to stored article existence; and switch the light emitting device off when a predetermined time from a point at which the door is closed has elapsed. switch the light emitting device on when the door is opened; after the door is closed, sense whether or not a sensing signal received for each of the plurality of storage slots is changed from a previous sensing signal, and count storage time from a point at which the sensing signal is determined to have changed if the sensing signal is changed from stored article non-existence to stored article existence; and switch the light emitting device off when a predetermined time from a point at which the door is closed has elapsed.