Disclosed herein are a body fluid collecting device which is easy to operate to collect body fluid and which is capable of detecting specific components in body fluid with a small amount of sample, and a body fluid collecting device of the type integral with a sticking needle, which is simple in structure, is easy to assemble and permits easy control of sticking depth. The body fluid collecting device 1 has a needle accommodating part 2, a sensor 5, and a sensor holder 6. The needle accommodating section 2 has the sticking needle 4 including the needle body 41 and the hub 42, and the casing 3 to accommodate the sticking needle 4 such that it can move in the axial direction. The sensor 5 has the measuring part 51 at its distal end. The sensor 5 is held between the sensor holder 6 and the needle accommodating part 2. The sensor holder 6 is mounted on the distal end of the needle accommodating part 2. Such a part constitutes the second supporter 82. In the distal end of the sensor holder 6 is mounted the first supporter 81 which supports the vicinity of the measuring part 51. In addition, in the distal end of the sensor holder 6 is formed the blood duct 63 that introduces blood to the measuring part 51 after the blood has been squeezed out from the skin by sticking with the sticking needle 4.
