The invention relates to a device (1) for measuring the amount of a substance given off from a skin surface (30) by diffusion, by means of a measurement head which can be placed on the skin surface (30). The measurement head has at least two measuring devices (2) which are spaced apart from one another, wherein the total of at least two measuring devices (2) are movable independently of one another, so that when said devices are placed on the skin surface they can be adapted to the curvature of the skin surface (30).
