We have investigated the formation of a platinum thin film from a simple solution of dihydrogen hexachloroplatinate
in a low temperature range of 283 to 295 K by a pulse current technique. Despite the low temperature, the
platinum thin film observed with a confocal laser scanning microscope does not comprise particle aggregates but dense
layer with a small surface roughness that tends to saturate at an initial growth stage. The deposition rate and current
efficiency at a fixed average current density are evidently dependent on temperature. The analysis of the mol weight of
platinum deposit based on two electrochemical reactions proposed in platinum electrodeposition elucidates the temperature
dependence characterized by a thermal activation process.