A detecting apparatus for detecting information of a liquid object or
sample includes a transmission path, a THz wave supplying unit, a THz
wave detecting unit, and an infiltrative holding member for infiltration
and holding of a liquid object. The supplying unit supplies an
electromagnetic wave in a frequency range between 30 GHz and 30 THz to
the transmission path. The detecting unit detects the THz wave
transmitted through the transmission path. The infiltrative holding
member is set at a location containing at least a portion in which an
electric field distribution of the THz wave propagating along the
transmission path extends.