To provide a cartridge for an electric stapler that is removable in a single-action operation.

The cartridge for an electric stapler comprises a cartridge body 12 mounted on a stapler body 2, and arms 16 arranged on the sides of the cartridge body 12, and the arms 16 have a locking projection 18 locked on a projection 8 on the stapler body 2, and a projected portion 19 for unlocking the locking portion 18 from the projection 8 when pressured, so that the cartridge body 12 can be withdrawn back from the stapler body 2. when the projected portions 19 are pressured to unlock the locking portions 18. The cartridge body 12 has a longitudinally movable knob 40 on the back. A backward movement of the knob 40 pressures the projected portions 19 of the arms 16 to unlock the locking portions 18 and thereafter withdraw the cartridge body I2 back from the stapler body 2.