Drug injection device with acceleration sensor for detecting abnormal operation

A drug injection device, comprising:

• a main body case having an injection needle let-in/let-out opening;
• a syringe unit inside the main body case and configured to be equipped with a drug syringe therein, the syringe unit comprising a piston and a first drive motor which drives the piston;
• a second drive motor configured to drive the syringe unit;
• a controller electrically connected to the first drive motor and the second drive motor;
• and
• an acceleration sensor electrically connected to the controller and being configured to detect acceleration applied to the main body case,
• wherein the controller stops the syringe unit from moving toward the injection needle let-in/let-out opening, or retracts the syringe unit away from the injection needle let-in/let-out opening, when the acceleration sensor has detected an acceleration of at least a first set value.