A method for producing crystals (3, 13) wherein the crystals (3, 13) are grown from a liquefying raw material (2, 12) in a crucible (1, 11) retained in a furnace and slowly cooling a melt of the raw material in the crucible (1, 11) from below upward, said method being characterized by comprising: controlling heaters so as to have a lower temperature area than a crystallization temperature downward and a higher temperature area than the crystallization temperature above thereof in a temperature distribution (5, 15) in a vertical direction in the furnace in which the crucible (1, 11) is retained, supplying a resupply raw material (9, 19, 19a, 19b) supplied from a raw material supply apparatus (8, 18, 18a, 18b) to a reflection plate (20, 22) placed above the crucible (1, 11) to drop the resupply raw material (9, 19, 19a, 19b) from the reflection plate (20, 22) into the crucible (1, 11) as the melt, wherein the reflection plate has a shape for holding the resupply raw material on a surface, for liquefying the resupply raw material (9, 19, 19a, 19b) by an overheating treatment when the crystals (3, 13) are grown from the melt, and for dropping the liquefied resupply raw material (9, 19, 19a, 19b) into the crucible (1, 11), and wherein the resupply raw material (9, 19, 19a, 19b) is liquefied by the reflection plate (20, 22) by heating at the same temperature as an overheating treatment temperature when the crystals (3, 13) are grown from the melt which is 20 to 100 °C higher than a crystallization temperature; and wherein the reflection plate (20, 22) is in a funnel shape, which narrows from above downward and provided with a drop opening which drops the liquid raw material into the crucible (1, 11) at its bottom portion, and has a plurality of grooves (32, 33) from its extension to the drop opening on an inner surface of the funnel shape so that the resupply raw material (9, 19, 19a, 19b) is held on the surface for a certain time; or wherein the reflection plate (20, 22) is in a bugle shape, which expands downward, and has a plurality of grooves (32, 33) from its center to the extension on an outer surface of the bugle shape so that the resupply raw material (9, 19, 19a, 19b) is held on the surface for a certain time. controlling heaters so as to have a lower temperature area than a crystallization temperature downward and a higher temperature area than the crystallization temperature above thereof in a temperature distribution (5, 15) in a vertical direction in the furnace in which the crucible (1, 11) is retained, supplying a resupply raw material (9, 19, 19a, 19b) supplied from a raw material supply apparatus (8, 18, 18a, 18b) to a reflection plate (20, 22) placed above the crucible (1, 11) to drop the resupply raw material (9, 19, 19a, 19b) from the reflection plate (20, 22) into the crucible (1, 11) as the melt, wherein the reflection plate has a shape for holding the resupply raw material on a surface, for liquefying the resupply raw material (9, 19, 19a, 19b) by an overheating treatment when the crystals (3, 13) are grown from the melt, and for dropping the liquefied resupply raw material (9, 19, 19a, 19b) into the crucible (1, 11), and wherein the resupply raw material (9, 19, 19a, 19b) is liquefied by the reflection plate (20, 22) by heating at the same temperature as an overheating treatment temperature when the crystals (3, 13) are grown from the melt which is 20 to 100 °C higher than a crystallization temperature; and wherein the reflection plate (20, 22) is in a funnel shape, which narrows from above downward and provided with a drop opening which drops the liquid raw material into the crucible (1, 11) at its bottom portion, and has a plurality of grooves (32, 33) from its extension to the drop opening on an inner surface of the funnel shape so that the resupply raw material (9, 19, 19a, 19b) is held on the surface for a certain time; or wherein the reflection plate (20, 22) is in a bugle shape, which expands downward, and has a plurality of grooves (32, 33) from its center to the extension on an outer surface of the bugle shape so that the resupply raw material (9, 19, 19a, 19b) is held on the surface for a certain time.