Disclosed is a flow rate control apparatus for controlling hydraulic oil flow supplied from a hydraulic pump to a working device and an option device. The flow rate control apparatus according to the present invention provides the flow rate control apparatus of construction equipment comprising: a boom cylinder driven by the hydraulic oil of a first hydraulic pump; a first control valve for controlling the hydraulic oil flow supplied to the boom cylinder; an option device driven by the hydraulic oil of a second hydraulic pump; a second control valve for controlling the hydraulic oil flow supplied to the option device; an operating lever for the boom cylinder and an operating lever for the option device; a merging line for selectively merging the hydraulic oil supplied to the boom cylinder into the option device; a center bypass switching valve which is installed at the most downstream side of a supply passage of the first hydraulic pump; a merging switching valve for selectively opening and closing the mergin
