A liquid chromatograph includes a mobile phase supplying apparatus including liquid-feeding pumps to feed mobile phases, liquid-feeding flow paths, a mixer to mix the mobile phases, at least one control device to control each liquid-feeding pump, flow rate measuring sections provided downstream in each liquid-feeding flow path configured to measure an actual flow rate and to detect a back-flow, and actual flow rate computing sections configured to compute an actual flow rate in the corresponding liquid feeding flow path. Also included are a sample injecting section downstream of the mobile phase supplying apparatus, a separating column for separating an injected sample into its constituents, and a detector for detecting each of the separated constituents. When one of the actual flow rate measuring sections detects a back-flow, the corresponding actual flow-rate computing section computes an actual back-flow rate and outputs a signal to the corresponding control device to cancel the back-flow.