Disclosed is an assistance device (10) which can be used for the puncture into the skin with a puncture tool (14) having a puncture needle (30) and the measurement of a desired component in the blood with a blood glucose monitoring system (12) equipped with a measurement tool (20). The assistance device (10) comprises a main body (38) which contacts with the skin and a lid (11) which is connected to the main body (38) in a freely openable and closable manner, wherein one of the main body (38) and the lid (11) has a puncture guide (74) for positioning the puncture needle (30) toward a position on the skin to be punctured with the puncture needle (30), and the other has a blood collection guide (46) for positioning the measurement tool (20) toward the position on the skin punctured with the puncture needle (30).
