A duplicate feeding detection device for use with sheet-like members may include a control part for controlling an ultrasonic transmission part, a duplicate feeding judging part for judging duplicate feeding of the sheet-like members on a basis of an output from an ultrasonic receiving part, a temperature measuring part for measuring temperature of a vicinity of the ultrasonic transmission part, and a memory part in which a relationship between an oscillation frequency of the ultrasonic transmission part and a temperature is stored. The control part sets an oscillation frequency corresponding to a temperature which is measured by the temperature measuring part on a basis of the relationship between the oscillation frequency and the temperature stored in the memory part.