A variable valve mechanism of an internal combustion engine, comprising: a cam that rotates with rotation of the internal combustion engine; and a transmission mechanism that transmits a profile of the cam to a valve to drive the valve, characterized in that the variable valve mechanism further comprises: a first variable device that controls the transmission mechanism to continuously change at least a maximum lift amount of a lift curve indicating a lift amount of the valve that corresponds to a rotation angle of the internal combustion engine; and a second variable device that controls the transmission mechanism to continuously change at least an operation angle (θ) of the lift curve, wherein, when the lift curve lies in any condition within a predetermined range that covers all or part of a variable range of the lift curve, an absolute value of a ratio (dL/dθ) of a maximum lift amount variation (dL) to an operation angle variation (dθ) for a slight change from the condition caused by the first variable device is larger than that for a slight change from the condition caused by the second variable device, the variable valve mechanism being characterized in that the transmission mechanism includes four links (21 to 24) coupled to one another via joints (31 to 33), the first variable device shifts at least a reciprocating motion direction of a predetermined joint when the valve is driven, and the second variable device shifts at least a position of the predetermined joint during a base-circle time in which a base circle of the cam acts. a cam that rotates with rotation of the internal combustion engine; and a transmission mechanism that transmits a profile of the cam to a valve to drive the valve, characterized in that the variable valve mechanism further comprises: a first variable device that controls the transmission mechanism to continuously change at least a maximum lift amount of a lift curve indicating a lift amount of the valve that corresponds to a rotation angle of the internal combustion engine; and a second variable device that controls the transmission mechanism to continuously change at least an operation angle (θ) of the lift curve, wherein, a first variable device that controls the transmission mechanism to continuously change at least a maximum lift amount of a lift curve indicating a lift amount of the valve that corresponds to a rotation angle of the internal combustion engine; and a second variable device that controls the transmission mechanism to continuously change at least an operation angle (θ) of the lift curve, wherein, when the lift curve lies in any condition within a predetermined range that covers all or part of a variable range of the lift curve, an absolute value of a ratio (dL/dθ) of a maximum lift amount variation (dL) to an operation angle variation (dθ) for a slight change from the condition caused by the first variable device is larger than that for a slight change from the condition caused by the second variable device, the variable valve mechanism being characterized in that the transmission mechanism includes four links (21 to 24) coupled to one another via joints (31 to 33), the first variable device shifts at least a reciprocating motion direction of a predetermined joint when the valve is driven, and the second variable device shifts at least a position of the predetermined joint during a base-circle time in which a base circle of the cam acts.