A method for monitoring a surface position of a melt in a crucible in a process of silicon single crystal growth by the Czochralski method using a melt surface position at the time of seeding as a reference position, the method comprising: observing a melt surface position, observing a position of the crucible, memorizing the shape of the silicon single crystal pulled up from the melt surface, calculating an estimated melt surface position based on the melt surface position as observed, the position of the crucible as observed, and the shape of the silicon single crystal as memorized, and transmitting information about the estimated melt surface position to a sequence circuit at an interval of control period to control the raising and lowering of the crucible, when the estimated melt surface position passes a preset upper limit position, stopping the crucible from raising. and wherein as the estimated melt surface position on the occasion of immersion of the silicon single crystal, pulled up in the course of growing, into the melt for remelting in the neck growth process, shoulder growth process, cylindrical body growth process or tail growth process, a relative liquid surface position h 3 is adopted, which is obtained from h 3 = h 2 + ∑ − GS × S D 2 × SM GL × C D 2 − GS × S D 2 + GL × C D 2 × CM GL × C D 2 − GS × S D 2 where h 3: relative liquid surface position from the reference position on the occasion of immersion of the silicon single crystal into the melt, h 2: relative liquid surface position from the reference position in the state of the silicon single crystal being separated from the melt, GS: specific gravity of solid silicon, GL: specific gravity of liquid silicon, SM: moving distance of the seed after separation of the silicon single crystal from the melt, CM:moving distance of the crucible after separation of the silicon single crystal from the melt, SD: diameter of the silicon single crystal pulled up from the melt surface, and CD: diameter of the melt surface. observing a melt surface position, observing a position of the crucible, memorizing the shape of the silicon single crystal pulled up from the melt surface, calculating an estimated melt surface position based on the melt surface position as observed, the position of the crucible as observed, and the shape of the silicon single crystal as memorized, and transmitting information about the estimated melt surface position to a sequence circuit at an interval of control period to control the raising and lowering of the crucible, when the estimated melt surface position passes a preset upper limit position, stopping the crucible from raising. and wherein as the estimated melt surface position on the occasion of immersion of the silicon single crystal, pulled up in the course of growing, into the melt for remelting in the neck growth process, shoulder growth process, cylindrical body growth process or tail growth process, a relative liquid surface position h 3 is adopted, which is obtained from h 3 = h 2 + ∑ − GS × S D 2 × SM GL × C D 2 − GS × S D 2 + GL × C D 2 × CM GL × C D 2 − GS × S D 2 where h 3: relative liquid surface position from the reference position on the occasion of immersion of the silicon single crystal into the melt, h 2: relative liquid surface position from the reference position in the state of the silicon single crystal being separated from the melt, GS: specific gravity of solid silicon, GL: specific gravity of liquid silicon, SM: moving distance of the seed after separation of the silicon single crystal from the melt, CM:moving distance of the crucible after separation of the silicon single crystal from the melt, SD: diameter of the silicon single crystal pulled up from the melt surface, and CD: diameter of the melt surface. where h 3: relative liquid surface position from the reference position on the occasion of immersion of the silicon single crystal into the melt, h 2: relative liquid surface position from the reference position in the state of the silicon single crystal being separated from the melt, GS: specific gravity of solid silicon, GL: specific gravity of liquid silicon, SM: moving distance of the seed after separation of the silicon single crystal from the melt, CM:moving distance of the crucible after separation of the silicon single crystal from the melt, SD: diameter of the silicon single crystal pulled up from the melt surface, and CD: diameter of the melt surface.