Sensor insertion device

A sensor insertion device for inserting a sensor for measuring biological information into a body of a patient, the sensor insertion device comprising:

• a cylindrical main body case having a lower end opening and an upper end opening;
• a needle insertion button that is disposed slidably in and out of the upper end opening on an inside of the cylindrical main body case, and configured to be operated by a user when performing needle insertion;
• a carrier that is provided in the cylindrical main body case and linked to the needle insertion button;
• a guide needle holder that is provided at a lower end portion of the carrier and configured to detachably hold a guide needle that is configured to be inserted into the body of the patient when guiding the sensor in an insertion direction;
• a cylindrical needle extraction sleeve that is provided slidably around an outer periphery of the cylindrical main body case;
• and
• a grip portion that is provided along a lengthwise direction of the cylindrical main body case on an outer peripheral surface side of the cylindrical needle extraction sleeve, and configured to be gripped by a hand of the user when inserting the sensor;
• wherein:
• the grip portion has a finger rest collar that is provided at an upper end portion of the grip portion, and protrudes in a direction intersecting the insertion direction;
• the finger rest collar has a cutout recess for guiding a finger of the user;
• and
• a cutout is defined at an upper end of the needle insertion button on a same side as the cutout recess of the finger rest collar.