Sheet processing apparatus capable of saving trouble of user and processing condition setting method

A sheet processing apparatus, comprising:

• a sheet feed cassette which stores a sheet;
• and
• a processor functioning as
• a detection processing portion which detects a sheet size of a stored sheet stored in the sheet feed cassette,
• a first acceptance processing portion which accepts a first designation operation for designating sheet information including one or more pieces of first attribute information related to a sheet size and second attribute information related to a sheet attribute different from the sheet size,
• a display processing portion which causes a setting screen to be displayed when any of the one or more pieces of first attribute information included in the sheet information designated by the first designation operation is predetermined specific attribute information, the setting screen including a sheet size detected by the detection processing portion and the second attribute information included in the sheet information as information used for setting a processing condition of the stored sheet,
• a setting processing portion which sets the processing condition based on information included in the setting screen,
• a second acceptance processing portion which causes some of sheet sizes used for setting the processing condition to be displayed according to a specific operation corresponding to the sheet size detected by the detection processing portion, that is included in the setting screen, and accepts a second designation operation for designating any of the displayed sheet sizes, and
• a change processing portion which changes, according to the second designation operation, the sheet size included in the setting screen from the sheet size detected by the detection processing portion to a sheet size designated by the second designation operation, wherein
• the first acceptance processing portion causes respective pieces of identification information for a plurality of pieces of the sheet information registered in the sheet processing apparatus in advance to be displayed in a selectable manner and accepts the first designation operation for designating any of the pieces of identification information displayed, and
• the second acceptance processing portion causes only one or more sheet sizes and the sheet size detected by the detection processing portion out of the sheet sizes used for setting the processing condition to be displayed in a selectable manner according to the specific operation and accepts the second designation operation, the one or more sheet sizes respectively corresponding to one or more pieces of the first attribute information different from the specific attribute information included in the sheet information designated by the first designation operation.