The invention relates to an insertion device (110) for inserting an analyte sensor (114) into a body tissue. The insertion device (110) comprises an insertion needle holder (120) and a drive mechanism (124) for driving the insertion needle holder (120) in a longitudinal direction (126). The drive mechanism (124) comprises at least one actuator (132) for actuating the drive mechanism (124). The drive mechanism (124) comprises a rotor (142) adapted to transform an actuation motion of the actuator (132) into a motion of the insertion needle holder (120) in the longitudinal direction (126). The insertion device (110) further comprises at least one safety lock (164). The safety lock (164), in a locked position, is adapted to at least partially block a rotation of the rotor (142). In an unlocked position, the safety lock (164) is adapted to permit the rotation of the rotor (142).