The present invention provides a lancet (X1) which includes a case (1) including an internal space (10), and a lancing unit (2) which includes a lancing needle (20) and which is movable within the internal space (10) in an advancing direction from a wait position to an advanced position. The case (1) includes a main body (11) accommodating the lancing unit (2), and a cap (12) which is molded integral with the main body (11) and detachable from the main body (11). The lancing unit (2) includes a cover portion (22) for covering a portion of the lancing needle (20) on the advancing side, for example. The cover portion (22) is detachable together with the cap (12) by exerting a rotational force for rotating the cap (12) and a pulling force for causing relative movement of the cap (12) in the advancing direction for exposing a front end of the lancing needle (20).