  We discuss the BPS configurations of IIB strings in the 7-brane background
from M-theory viewpoint. We first obtain the hyperkahler geometry background of
M-theory expected from the 7-brane solutions of the type IIB supergravity. We
choose the appropriate complex structures of the background geometries and
embed a membrane of M-theory holomorphically to obtain a BPS string
configuration. The recently discussed BPS string configurations such as
3-string junctions and string networks in the flat background are generalized
to the cases with the 7-brane backgrounds. The property of the BPS string
configurations in the 7-brane backgrounds is in agreement with the previously
known results from the IIB string viewpoint.
