Injection pen body for manually pushing and injecting insulin

The injection pen body comprises a shell, a scale adjusting sleeve is arranged in the shell, the upper portion of the scale adjusting sleeve is a holding portion, and the holding portion is located above the shell. An excitation button, a lock rod and a spring are sequentially mounted on the inner side of the upper part of the scale adjusting sleeve from top to bottom; the inner side of the scale adjusting sleeve is connected with an adjusting screw sleeve and a push rod; the lower portion of the adjusting threaded sleeve is connected with an adjusting nut, the adjusting nut is fixed in the lower portion of the shell, a rear cover is fixed below the adjusting nut, a threaded rod is arranged in the rear cover in a penetrating mode, the threaded rod is in sliding connection with a push rod, the push rod is in sliding connection with a locking rod, and a scale adjusting sleeve is in sliding connection with the adjusting threaded sleeve. The insulin injection pen meets various design specification requirements of