A refrigerator, comprising: a main body; a door (125, 135) coupled to the main body; an ice maker installed at the door (125, 135), the ice maker comprising: an ice tray for making ice cubes; an ejector for ejecting the ice cubes from the ice tray; a slider oriented at an incline to guide the ice cubes ejected by the ejector;and an ice separation heater for heating up the ice tray to separate the ice cubes made in the ice tray; wherein the refrigerator further comprises: a storage container mounted below the ice maker; and a sensing apparatus (220, 320) configured to sense an ice level in the storage container, the sensing apparatus (220, 320) comprising: an optical element having: a transmitting module for sending a signal, and a receiving module for receiving the signal sent by the transmitting module; and at least one alignment device that aligns and secures the optical element in a preset direction, characterized in that the ice maker further comprises a holder configured to accommodate the ice separation heater, wherein the holder is disposed below the ice tray, and wherein the sensing apparatus (220, 320) is mounted at the holder. a main body; a door (125, 135) coupled to the main body; an ice maker installed at the door (125, 135), the ice maker comprising: an ice tray for making ice cubes; an ejector for ejecting the ice cubes from the ice tray; a slider oriented at an incline to guide the ice cubes ejected by the ejector;and an ice separation heater for heating up the ice tray to separate the ice cubes made in the ice tray; an ice tray for making ice cubes; an ejector for ejecting the ice cubes from the ice tray; a slider oriented at an incline to guide the ice cubes ejected by the ejector;and an ice separation heater for heating up the ice tray to separate the ice cubes made in the ice tray; wherein the refrigerator further comprises: a storage container mounted below the ice maker; and a sensing apparatus (220, 320) configured to sense an ice level in the storage container, the sensing apparatus (220, 320) comprising: an optical element having: a transmitting module for sending a signal, and a receiving module for receiving the signal sent by the transmitting module; and at least one alignment device that aligns and secures the optical element in a preset direction, characterized in that the ice maker further comprises a holder configured to accommodate the ice separation heater, wherein the holder is disposed below the ice tray, and wherein the sensing apparatus (220, 320) is mounted at the holder. a storage container mounted below the ice maker; and a sensing apparatus (220, 320) configured to sense an ice level in the storage container, the sensing apparatus (220, 320) comprising: an optical element having: a transmitting module for sending a signal, and a receiving module for receiving the signal sent by the transmitting module; and at least one alignment device that aligns and secures the optical element in a preset direction, characterized in that the ice maker further comprises a holder configured to accommodate the ice separation heater, wherein the holder is disposed below the ice tray, and wherein the sensing apparatus (220, 320) is mounted at the holder. an optical element having: a transmitting module for sending a signal, and a receiving module for receiving the signal sent by the transmitting module; and a transmitting module for sending a signal, and a receiving module for receiving the signal sent by the transmitting module; and at least one alignment device that aligns and secures the optical element in a preset direction, characterized in that the ice maker further comprises a holder configured to accommodate the ice separation heater, wherein the holder is disposed below the ice tray, and wherein the sensing apparatus (220, 320) is mounted at the holder.