To provide a dryer for drying sludge subjected to dewatering treatment by a solid-liquid separator, having a reduced size and improved sludge drying efficiency.

An oscillator 1 to be oscillated around an oscillation center CL has a first bottom plate 2, a second bottom plate 2A located under the first bottom plate 2, and a third bottom plate 2B located under the second bottom plate 2A. With the oscillator 1 being oscillated, the sludge is supplied onto the first bottom plate 2 and then carried onto the second bottom plate 2A and the third bottom plate 2B in sequence, whereby it is heated and dried.