A capillary-driven heat transfer device is adapted to extract heat from a heat source and release this heat to a cold source using a two-phase working fluid. The device includes an evaporator having a microporous mass performing capillary pumping of fluid in the liquid phase, a condenser, a reservoir having an inner chamber and an inlet and/or outlet port, a vapor communication circuit, connecting the outlet of the evaporator to the inlet of the condenser, a liquid communication circuit, and a non-return device arranged between the inner chamber of the reservoir and the microporous mass of the evaporator, and arranged to prevent liquid present in the evaporator from moving to the inner chamber of the reservoir.