An oil pressure control apparatus, comprising: a pump driven by a rotation of a driving power source for discharging an oil; a control apparatus including a driving side rotation member rotating synchronously to a crankshaft and a driven side rotation member arranged coaxially to the driving side rotation member and rotating synchronously to a camshaft, the control apparatus controlling an opening/closing timing of a valve by displacing a relative rotational phase of the driven side rotation member relative to the driving side rotation member by supplying or discharging the oil; a control valve mechanism being in communication with the pump via a first fluid passage and being in communication with the control apparatus via a second fluid passage for controlling to supply and discharge the oil relative to the control apparatus; a third fluid passage diverging from the first fluid passage to supply the oil to a predetermined portion other than the control apparatus; and a fluid passage dimension regulating mechanism including a movable member provided at the third fluid passage and including an opening (31 a) for regulating a fluid passage dimension of the third fluid passage, the movable member being biased to a side for increasing the fluid passage dimension by an application of an hydraulic pressure of the third fluid passage; wherein the fluid passage dimension regulating mechanism is in communication with a fourth fluid passage diverging from the second fluid passage and biases the movable member to the side increasing the fluid passage dimension by applying the hydraulic pressure of the fourth fluid passage to the movable member separately from the hydraulic pressure of the third fluid passage. a pump driven by a rotation of a driving power source for discharging an oil; a control apparatus including a driving side rotation member rotating synchronously to a crankshaft and a driven side rotation member arranged coaxially to the driving side rotation member and rotating synchronously to a camshaft, the control apparatus controlling an opening/closing timing of a valve by displacing a relative rotational phase of the driven side rotation member relative to the driving side rotation member by supplying or discharging the oil; a control valve mechanism being in communication with the pump via a first fluid passage and being in communication with the control apparatus via a second fluid passage for controlling to supply and discharge the oil relative to the control apparatus; a third fluid passage diverging from the first fluid passage to supply the oil to a predetermined portion other than the control apparatus; and a fluid passage dimension regulating mechanism including a movable member provided at the third fluid passage and including an opening (31 a) for regulating a fluid passage dimension of the third fluid passage, the movable member being biased to a side for increasing the fluid passage dimension by an application of an hydraulic pressure of the third fluid passage; wherein the fluid passage dimension regulating mechanism is in communication with a fourth fluid passage diverging from the second fluid passage and biases the movable member to the side increasing the fluid passage dimension by applying the hydraulic pressure of the fourth fluid passage to the movable member separately from the hydraulic pressure of the third fluid passage.