  We have made multi-epoch VLBI observations of H2O maser emission in the
massive star forming region IRAS 06061+2151 with the Japanese VLBI network
(JVN) from 2005 May to 2007 October. The detected maser features are
distributed within an 1\arcsec$\times$1\arcsec (2000 au$\times$2000 au at the
source position) around the ultra-compact H {\small\bf II} region seen in radio
continuum emission. Their bipolar morphology and expanding motion traced
through their relative proper motions indicate that they are excited by an
energetic bipolar outflow. Our three-dimensional model fitting has shown that
the maser kinematical structure in IRAS 06061+2151 is able to be explained by a
biconical outflow with a large opening angle ($>$ 50\degr). The position angle
of the flow major axis coincides very well with that of the large scale jet
seen in 2.1$\:\mu\rmn{m}$ hydrogen emission. This maser geometry indicates the
existence of dual structures composed of a collimated jet and a less collimated
massive molecular flow. We have also detected a large velocity gradient in the
southern maser group. This can be explained by a very small (on a scale of
several tens of au) and clumpy (the density contrast by an order of magnitude
or more) structure of the parental cloud. Such a structure may be formed by
strong instability of shock front or splitting of high density core.
