We developed a novel ice-core laser melting sampler (LMS) to measure the stable water isotope ratios (δ18O and δD) as temperature proxies at ultra-high depth resolutions. In this LMS system, a 2-mm diameter movable evacuation nozzle holds an optical fiber through which a laser beam irradiates the ice core. The movable nozzle intrudes into the ice core, the laser radiation meanwhile melting the ice cylindrically, and the meltwater is pumped away simultaneously through the same nozzle and transferred to a vial for analysis. To avoid isotopic fractionation of the ice-core components by vaporization, the laser power is adjusted to ensure that the temperature of the meltwater is always kept well below its boiling point. Internal contamination and cross-contamination were both found to be negligible using this LMS. A segment of a Dome Fuji shallow ice core (Antarctica), using the LMS, was then demonstrated to have been discretely sampled with a depth-resolution as small as 3 mm: subsequent measurements of δ18O and δD were reasonably consistent with results obtained by hand segmentation. The LMS will thus enable us to seek the past temperature variations that may appear even in sub-centimeter resolutions in ice cores.