FIELD: power engineering. SUBSTANCE: invention relates to design of autonomous tidal damless low-power power plants and can be used to convert energy of sea currents (tides) into electric energy. Purpose: provision of power to remote consumers deprived of main electric networks. Tidal hydroelectric power plant comprises a pneumatic-hydraulic chamber, the underwater part of which is located at the bottom of the reservoir, and surface is communicated with atmosphere through pressure air duct, air turbine, kinematically connected to electric generator, elastic gas holder located at bottom of water reservoir. Chamber is equipped near the bottom in the zone of tide with water inlet-outlet holes and a hole on the upper end, on which the valve box is located. Box has two holes, one of which is equipped with valve spring-loaded for closing, connected to pressure air duct, and the other opening is connected through a local air duct, a check valve and a common air duct to the inlet of the gas holder, wherein from the outlet of the latter the compressed air is supplied to the air turbine by means of an air duct. In order to increase HPP power at water reservoir bottom in zone of water inflow there can be installed several pneumohydraulic chambers, additional local air ducts of which through additional check valves are connected to common gas duct of gas holder. Also, to increase HPP capacity as an air turbine, a volumetric flow meter is used, and an additional load distributed on its surface is placed on the gas head. EFFECT: simplified design and operation of the device in automatic mode without the need for continuous maintenance.