It is shown that unconventional critical phenomena commonly observed in paramagnetic metals YbRh(2)Si(2), YbRh(2)(Si(0.95)Ge(0.05))(2), and beta-YbAlB(4) are naturally explained by the quantum criticality of Yb-valence fluctuations. We construct the mode-coupling theory taking account of local correlation effects of f electrons and find that unconventional criticality is caused by the locality of the valence fluctuation mode. We show that measured low-temperature anomalies such as divergence of uniform spin susceptibility chi similar to T(-zeta) with zeta similar to 0.6 giving rise to a huge enhancement of the Wilson ratio and the emergence of T-linear resistivity are explained in a unified way.