The present invention is a cleaning member and an elastic member that can prevent decreases in wiping performance even when raised in temperature due to use in a high-temperature environment or use over a long period. Provided is a cleaning member, comprising an elastic member that includes polyurethane, wherein: when tanδ of a test piece sampled from the elastic member is measured in the temperature range of -20°C to +60°C, the peak temperature of a peak indicating the maximum value of tanδ is at 15.0°C or below; the maximum value of tanδ is 0.20 to 0.55; tanδ at a temperature of 55°C is 0.13 or larger; and where the detected quantity of all ions obtained when the test piece is heated at a rate of temperature increase of 10°C/second to 1000°C using a direct-sampling mass spectrometer is M1 and the integrated intensity of a peak in a derived ion thermogram that corresponds to a range of m/z values originating in multifunctional isocyanate with at least three isocyanate groups is M2, M2/M1 is at least 0.001.