A binary encoder which has a fast conversion speed, occupies a small area, and consumes a small amount of power is provided. The binary encoder includes first and second latch transistors, first and second charge transistors, first and second control transistors, first and second discharge transistors, an equalize transistor, and first and second inverters. The first charge transistor charges a first output node to a level of a power voltage in response to a clock signal. The second charge transistor charges a second output node to the level of the power voltage in response to the clock signal. The first discharge transistor discharges a first control node to a level of a ground voltage in response to a first input signal. The second discharge transistor discharges a second control node to the level of the ground voltage in response to a second input signal.