The main field for drilling holes in ice is polar research associated with drilling a floating ice in order to analysing the lower surface thereof, subjacent water and sea bottom. Actually, heat drilling heads or hydraulic drilling heads operating with hot water are used. Said drilling heads make it possible only to drill holes whose diameter corresponds to a drilling tool diameter, thereby making it difficult to detach and withdraw the drilling tools and measuring devices. The inventive method is directed to producing a large and uniform drilling diameter by combining heat and hydraulic drillings wherein the hydraulic drilling is carried out on the radial plane of the drilling hole using preferably a heat-hydraulic drilling head (1) which comprises an axial water inlet (2) in the top section thereof and an azimuthal peripheral annular gap (5) which is arranged above and below a hemispheric fusion area (3), is tightly connected to the water inlet (2) and covers a large area. Said annular gap makes it possible to deviate hot water (4) towards the drilling hole (7) and upward, thereby making it possible to produce a smooth drilling surface (14) and a constant drilling diameter (15). Said heat-hydraulic drilling head (1) closes a predrilled hole (9) with a meltwaterfilm (12), thereby preventing sucking cold seawater to the end of a main drilling hole (19).