The effects of confinement in channels between single-walled carbon nanotubes (SWNTs) on the water to ice transition temperature are studied in this work. The channels are provided in the SWNT rope, which are formed between SWNTs when SWNT films are treated with diamond wire drawing dies. Gold wires and aluminum tapes are used as electrodes to connect SWNT rope. When we carried out the measurement, a part of SWNT rope was dipped into water, and the electrical property of the SWNT rope was monitored with decreasing temperature. A sharp jump in voltage is found when the temperature is 274.1 K, which represents the transition temperature of confined water in the channels between SWNTs. These results indicate that the temperature of water-ice transition increases due to its confinement in nanometer size channels compared to that of bulk water. The mechanisms of our observation are discussed. (C) Koninklijke Brill NV, Leiden, 2011