The new-generation high-granularity Shashlyk EM calorimeter readout by micropixel avalanche photodiodes (MAPD) with precision thermostabilization based on the Peltier element is designed, constructed end tested. MAPD-3N with superhigh pixel density 1.5 x 10(4) mm(-2) and area 3 x 3 mm(2) manufactured by the Zecotek Company were used in the photodetector unit.