To solve the problem that the adhesion force of a paper band may be weakened when a temperature is low due to an influence of the temperature of an environment where a device is placed even if the temperature of a paper band-bonding means or a press part is stabilized at a constant temperature.

In a paper sheet-sealing method of binding accumulated paper sheets by bonding one end of the paper band that is laid on the paper sheets and cut by a cutter to the other end, the paper band is preliminarily warmed by a paper band warming part 104 mounted in a running passage of the running paper band let out of an accommodating part 97.