  For a field theory with a gravitational dual, following Susskind's proposal
we define holographic complexity for a subsystem. The holographic complexity is
proportional to the volume of a co-dimension one time slice in the bulk
geometry enclosed by the extremal co-dimension two hyper-surface appearing in
the computation of the holographic entanglement entropy. The proportionally
constant, up to a numerical order of one factor is G R where G is the Newton
constant and R is the curvature of the space time. We study this quantity in
certain holographic model. We also explore a possible relation between the
defined quantity and fidelity appearing in quantum information literature.
