A biosensor chip (1) includes: an electrode substrate (11) having a first principal surface (11a) provided with an electrode (151, 152) a cover film (14) opposed to the first principal surface (11a) a spacer layer (13) disposed between the electrode substrate (11) and the cover film (14), the spacer layer having a slit (13a) provided in a region positionally corresponding at least to the electrode (151, 152), the spacer layer serving as a bonding member to join the substrate (11) and the cover film (14) together and a hydrophilic filter (12) disposed between the spacer layer (13) and the substrate (11) and covering at least a portion of the electrode (151, 152), the portion of the electrode positionally corresponding to the slit (13a). A zone defined by the cover film (14), the slit (13a) of the spacer layer (13), and the electrode substrate (11) serves as a sample channel.
