To provide a method for more accurately calculating a master residual quantity having high reliability of a user and favorable usability by the frequency of a plate making, a device for more accurately calculating the master residual quantity by the frequency of the plate making, and a device for notifying the user of the master residual quantity by the frequency of the plate making.

For this master residual quantity calculating method, a residual master sensing means 88 which senses the residual master quantity, a range calculating means 24, used master detecting means 88 and 103, and a frequency calculating means 24 are used. The range calculating means 24 calculates to which one from among a plurality of residual ranges a ratio of the residual master quantity to a new master quantity belongs from the sensing result by the residual master sensing means 88. The used master sensing means 88 and 103 sense a master consumption quantity since the change of the residual range by the range calculating means 24. The frequency calculating means 24 calculates the plate making available frequency from the master consumption quantity sensed by the used master sensing means 88 and 103.