Recent radio very long baseline interferometry (VLBI) observations reveal a triple-ridge emission structure of the relativistic jet in M 87 radio galaxy that consists of the conventional limb-brightened feature and a narrow central ridge. Motivated by these observations, we examine a steady axisymmetric force-free model of a jet driven by the central black hole with its electromagnetic structure being consistent with general relativistic magnetohydrodynamic (GRMHD) simulations, and shown that the model with a velocity field associated with the electromagnetic field and a simple Gaussian distribution of emitting electrons at the jet base can produce the triple-ridge structure. This study will be complementary to theoretical analyses of the future observations of active galactic nucleus (AGN) jets.