The present invention relates to a pen-type portable insulin injection device, and more particularly, to a pen-type portable insulin injection device having an automatic/manual injection function which is switched in accordance with the selection of a user. The pen-type portable insulin injection device according to the present invention comprises a driving unit, a piston-pushing unit and automatic/manual injection switching means. The piston-pushing unit comprises: a pusher housing which has a through-hole formed in a lengthwise direction and which is rotatably connected to a case a transmission shaft, one end of which is connected to a gearbox so as to receive rotating force from the gearbox, and which is inserted into the through-hole of the pusher housing and a pusher installed and restricted within the through-hole of the pusher housing such that the pusher receives rotating force from the transmission shaft and slides in a lengthwise direction within the through-hole of the pusher housing. The automatic/manual injection switching means restricts, in a first position, the case and the pusher housing to prevent a relative rotation between the case and the pusher housing, and also releases any one of a plurality of gears of the gearbox so as to enable the rotating force of a motor to be transmitted to the transmission shaft. The automatic/manual injection switching means releases, in a second position, the case and the pusher housing to enable a relative rotation between the case and the pusher housing, and also restricts the rotation of any one of the plurality of gears of the gearbox so as to prevent the rotating force of the motor from being transmitted to the transmission shaft.La présente invention a pour objet un dispositif dinjection dinsuline portatif de type stylo, et plus particulièrement un dispositif dinjection dinsuline portatif de type stylo ayant une fonction dinjection automatique / manuelle qui est commutée au gré de lutilisateur. Le dispositif d
