An image forming apparatus including an image forming section to perform image formation based on a plurality of jobs, comprising: at least a two paper feeding trays each comprising a sensor to detect the remaining amount of paper stored in said paper feeding tray, a control section, which is configured to calculate the number of sheets of paper necessary to perform the job,and to judge whether said remaining amount of paper stored in said paper feeding tray to be used in performing said job is sufficient to complete said job, before the plurality of jobs are performed by the image forming section; the control section which is configured to calculate the timing to automatically switch the paper feeding trays according to a priority order of switching the paper feeding trays to be used in performing the job; the control section to allow a display section to display switching information before the plurality of jobs are performed by the image forming section, wherein the switching information shows that said paper feeding tray to be used in performing the job is to be switched to said other paper feeding tray in case said remaining amount of paper stored in said first paper feeding tray to be used in performing said job is not sufficient to complete said job, as a result of calculations by said control section based on said remaining amount of paper stored in said paper feeding tray detected by said sensor; and said information further includes paper feeding tray information arranged along either one of a vertical axis (71 B) or horizontal axis of a display screen of said display section comprising present paper remaining amount information, and information of job performing time or number of sheets of paper to be used, and information showing estimated remaining amount of paper stored in said paper feeding tray to be used in performing the job, and information showing timing of switching of the paper feeding tray to be used in performing the job and information showing paper feeding tray to be switched to. at least a two paper feeding trays each comprising a sensor to detect the remaining amount of paper stored in said paper feeding tray, a control section, which is configured to calculate the number of sheets of paper necessary to perform the job,and to judge whether said remaining amount of paper stored in said paper feeding tray to be used in performing said job is sufficient to complete said job, before the plurality of jobs are performed by the image forming section; the control section which is configured to calculate the timing to automatically switch the paper feeding trays according to a priority order of switching the paper feeding trays to be used in performing the job; the control section to allow a display section to display switching information before the plurality of jobs are performed by the image forming section, wherein the switching information shows that said paper feeding tray to be used in performing the job is to be switched to said other paper feeding tray in case said remaining amount of paper stored in said first paper feeding tray to be used in performing said job is not sufficient to complete said job, as a result of calculations by said control section based on said remaining amount of paper stored in said paper feeding tray detected by said sensor; and said information further includes paper feeding tray information arranged along either one of a vertical axis (71 B) or horizontal axis of a display screen of said display section comprising present paper remaining amount information, and information of job performing time or number of sheets of paper to be used, and information showing estimated remaining amount of paper stored in said paper feeding tray to be used in performing the job, and information showing timing of switching of the paper feeding tray to be used in performing the job and information showing paper feeding tray to be switched to.