  The protostar B335 was observed in the 1.3 mm continuum and in the H2CO 312 -
211 line with an angular resolution of about 8 arcsec. The mass of the inner
envelope detected by the dust continuum emission is about 0.02 Msun. The H2CO
spectrum at the protostellar position shows a blue-skewed double peak profile,
suggesting that the kinematics of the inner envelope is dominated by infall
motion. When the blueshifted and the redshifted peaks were imaged separately,
however, there is a small east-west displacement between the maximum positions.
This displacement suggests that some part of the H2CO emission might come from
the outflowing gas. A combined effect of the infalling envelope and the outflow
on the radiative transfer is discussed. This effect can make the line profile
asymmetry severer than what is expected from infall-only models.
