FIELD: excavation equipment. SUBSTANCE: invention relates to the field of excavation equipment, namely to rotary excavators intended for the development of tranches for main pipelines. A working body of a rotary excavator consists of a rotor made in the form of a wheel with a diameter <i>D</i> with a rotary drive and buckets placed on the wheel in two parallel annular rows, each of which contains <i>n</i> buckets installed with an interval of π<i>D/n</i>. Moreover, buckets of the first row are located with circular displacement relatively to buckets of the second row. The working body is equipped with an additional annular row of <i>n</i> buckets, placed between the first and the second rows of buckets. Circular displacement of buckets of the additional row relatively to buckets of the first row and buckets of the second row relatively to buckets of the additional row is equal to π<i>D/3n</i>. Front cutting blades of buckets are made with an angular tilt relatively to the axis of the rotor. EFFECT: increase in the reliability of a working body. 1 cl, 3 dwg.