A surgical stapling device (10) has an elongated body (14) and a removable loading unit (16) and a securing structure for securing the loading unit onto the elongated body (14). A guiding ramp guides the movement of the loading unit as it is mounted onto the loading portion. The locking structure (510) has a first position for locking movement of the loading unit (16) and enabling firing rod (58) to engage the loading unit (16). The locking unit has a second position for allowing the loading unit (16) to be disengaged and removed from the device (10).
