To provide a paddle dryer for high-speed drying of sludge or the like, configured to use waste heat of an incinerator for heating for energy-saving, and to prevent clogging, seizure, or firing even if sludge or the like is recycled at a high speed and in bulk as an industry.

A drying chamber 36 and its outer periphery are covered with an upper plate 30, an inner plate 31, an outer plate 32, an input side plate 33, and a discharge side plate 34, to form a U-shaped cross-sectional space 38 in an upper part of an iron frame base 20. A main shaft 40 horizontally penetrating through the drying chamber 36 is provided with a plurality of paddles 41 so as to be rotated. Hot air passes through the U-shaped cross-sectional space 38. A discharge screw conveyer 44 is disposed at a bottom part of the inner plate 31 to penetrate the U-shaped cross-sectional space 38 and operate by a discharge motor MO. A load current I of a main shaft drive motor MP as an energy source rotating the main shaft 40 is detected to estimate moisture content G of the sludge, to actuate the discharge motor MO.