A wearable body composition analyzer comprising: an induction part (101, 201, 301, 401, 701) that induces a secretion of a bodily liquid while being in contact with a body part; a collection part (103, 203, 303, 403, 501, 502, 503, 504, 505, 601) that collects the bodily liquid secreted; a sensor part (105, 205, 305, 357, 405, 703) that detects a body composition from the bodily liquid collected by the collection part (103, 203, 303, 403, 501, 502, 503, 504, 505, 601), the sensor part (105, 205, 305, 357, 405, 703) comprising an operation electrode, a counter electrode arranged to be spaced apart from the operation electrode and an auxiliary electrode arranged to be spaced apart from the operation electrode and the counter electrode; and a wearable part (107, 307, 407, 707) detachably attached to at least one of the induction part (101, 201, 301, 401, 701) and the collection part (103, 203, 303, 403, 501,502,503,504,505,601), wherein the wearable part (107, 307, 407, 707) is configured to be worn on the body, and where the wearable body composition analyzer further comprises a driving circuit part (308, 387, 408, 708) that applies a signal to the induction part (101, 201, 301, 401, 701) and the sensor part (105, 205, 305, 357, 405, 703), the operation electrode being operated by the signal applied from the driving circuit part (308, 387, 408, 708), and where further the sensor part (105, 205, 305, 357, 405, 703) detects a current by a body composition between the operation electrode and the counter electrode, and where the driving circuit part (308, 387, 408, 708) applies a first current or a second current flow to the operation electrode, the first current being smaller than the second current, and the first current being applied until the the operation electrode is electrically connected to the auxiliary electrode via the bodily liquid, whereupon the second current is applied. an induction part (101, 201, 301, 401, 701) that induces a secretion of a bodily liquid while being in contact with a body part; a collection part (103, 203, 303, 403, 501, 502, 503, 504, 505, 601) that collects the bodily liquid secreted; a sensor part (105, 205, 305, 357, 405, 703) that detects a body composition from the bodily liquid collected by the collection part (103, 203, 303, 403, 501, 502, 503, 504, 505, 601), the sensor part (105, 205, 305, 357, 405, 703) comprising an operation electrode, a counter electrode arranged to be spaced apart from the operation electrode and an auxiliary electrode arranged to be spaced apart from the operation electrode and the counter electrode; and a wearable part (107, 307, 407, 707) detachably attached to at least one of the induction part (101, 201, 301, 401, 701) and the collection part (103, 203, 303, 403, 501,502,503,504,505,601), wherein the wearable part (107, 307, 407, 707) is configured to be worn on the body, and where the wearable body composition analyzer further comprises a driving circuit part (308, 387, 408, 708) that applies a signal to the induction part (101, 201, 301, 401, 701) and the sensor part (105, 205, 305, 357, 405, 703), the operation electrode being operated by the signal applied from the driving circuit part (308, 387, 408, 708), and where further the sensor part (105, 205, 305, 357, 405, 703) detects a current by a body composition between the operation electrode and the counter electrode, and where the driving circuit part (308, 387, 408, 708) applies a first current or a second current flow to the operation electrode, the first current being smaller than the second current, and the first current being applied until the the operation electrode is electrically connected to the auxiliary electrode via the bodily liquid, whereupon the second current is applied.