A drug delivery device comprising: a preloaded syringe including: a sterile hollow needle, a barrel in fluid communication with said sterile hollow needle, a distal end of said barrel rigidly attached to said sterile hollow needle, a plunger slidingly sealing a proximal end of said barrel, said plunger sliding distally thereby discharging a contents of said barrel out of said hollow needle, a flange at a proximal end of said barrel, and a needle cover preserving sterility of said sterile hollow needle; a proximal housing portion including: a motor assembly; and a transmission converting a rotation motion of said motor assembly to a linear motion; and a distal housing portion including: a channel fitting said preloaded syringe, said channel including a proximal opening large enough for inserting said preloaded syringe into said channel, a distal opening large enough to allow said sterile hollow needle to protrude from a distal end of said distal housing portion, wherein the drug delivery device is adapted that, when said syringe is inserted into said channel, said transmission is operationally connected to said plunger when a distal end of said proximal housing is joined to a proximal end of said distal housing, enabling discharging of said contents of said barrel by activating said motor, characterized in that, the distal housing includes an adhesive base for fastening said distal housing portion to a skin of a patient, the adhesive base including a needle aperture, in that an activation device is provided including: a handle accessible from outside of said channel, an attachment mechanism exposed to said channel, such that when said preloading syringe is fully inserted into said channel, said attachment mechanism attaches to said needle cover, a coupler (1871, 1971) passing through the needle aperture in said adhesive base, said coupler (1871, 1971) connecting said handle to said attachment mechanism, and an adhesive cover for said adhesive base connected to said handle by an extender for peeling said adhesive cover from said adhesive base. a preloaded syringe including: a sterile hollow needle, a barrel in fluid communication with said sterile hollow needle, a distal end of said barrel rigidly attached to said sterile hollow needle, a plunger slidingly sealing a proximal end of said barrel, said plunger sliding distally thereby discharging a contents of said barrel out of said hollow needle, a flange at a proximal end of said barrel, and a needle cover preserving sterility of said sterile hollow needle; a sterile hollow needle, a barrel in fluid communication with said sterile hollow needle, a distal end of said barrel rigidly attached to said sterile hollow needle, a plunger slidingly sealing a proximal end of said barrel, said plunger sliding distally thereby discharging a contents of said barrel out of said hollow needle, a flange at a proximal end of said barrel, and a needle cover preserving sterility of said sterile hollow needle; a proximal housing portion including: a motor assembly; and a transmission converting a rotation motion of said motor assembly to a linear motion; and a motor assembly; and a transmission converting a rotation motion of said motor assembly to a linear motion; and a distal housing portion including: a channel fitting said preloaded syringe, said channel including a proximal opening large enough for inserting said preloaded syringe into said channel, a distal opening large enough to allow said sterile hollow needle to protrude from a distal end of said distal housing portion, wherein the drug delivery device is adapted that, when said syringe is inserted into said channel, said transmission is operationally connected to said plunger when a distal end of said proximal housing is joined to a proximal end of said distal housing, enabling discharging of said contents of said barrel by activating said motor, characterized in that, the distal housing includes an adhesive base for fastening said distal housing portion to a skin of a patient, the adhesive base including a needle aperture, in that an activation device is provided including: a handle accessible from outside of said channel, an attachment mechanism exposed to said channel, such that when said preloading syringe is fully inserted into said channel, said attachment mechanism attaches to said needle cover, a coupler (1871, 1971) passing through the needle aperture in said adhesive base, said coupler (1871, 1971) connecting said handle to said attachment mechanism, and an adhesive cover for said adhesive base connected to said handle by an extender for peeling said adhesive cover from said adhesive base. a handle accessible from outside of said channel, an attachment mechanism exposed to said channel, such that when said preloading syringe is fully inserted into said channel, said attachment mechanism attaches to said needle cover, a coupler (1871, 1971) passing through the needle aperture in said adhesive base, said coupler (1871, 1971) connecting said handle to said attachment mechanism, and an adhesive cover for said adhesive base connected to said handle by an extender for peeling said adhesive cover from said adhesive base.