The present invention provides a novel pyrazole derivative and an androgen receptor antagonist containing the derivative. The present invention provides a compound represented by the formula (I′) wherein R1 is a hydrogen atom, a group via a carbon atom, a group via a nitrogen atom, a group via an oxygen atom, or a group via a sulfur atom; R2 is a phenyl group having cyano (the phenyl group may further have substituent(s) other than cyano); R3 is a hydrogen atom, a group via a carbon atom, a group via a nitrogen atom, a group via an oxygen atom, or a group via a sulfur atom; R4 is a cyclic group optionally having substituent(s); and X is methylene optionally having substituent(s), or CO, or a salt thereof.