A dryer includes a heater configured to heat an object to dry the object, a plurality of collection devices configured to collect a liquid generated by liquefication of condensed vapor in the dryer, a drainage tube configured to drain the liquid from each of the plurality of collection devices, a pump configured to feed the liquid through the drainage tube, a switch configured to switch a connection between the plurality of collection devices and the switch, and a pressure sensor configured to measure a pressure between the switch and the pump.