1. A nicotinamide derivative represented by the following formula (I) or a salt thereof: [Formula 1] where R is a substituent of formula (II-1), (III-1) or (IV-1): [Formula 2] (where R is an atom hydrogen or C 1-6 alkyl, C 1-6 cycloalkyl, phenyl, pyridyl or thienyl groups, each of which optionally contains at least one substituent, R 1 represents a hydrogen atom, C 1-6 alkyl group or C 1-6 cycloalkyl group, R 4 represents a hydroxy group, a halogen atom or a C 1-6 alkyl or C 1 alkoxy group, each of which is optional It contains at least one substituent, n is an integer from 0 to 2, when n is 2, R can be the same or different from each other, and two R, together with the carbon atom to which they are bonded, can form a cycloalkane the ring, X represents an oxygen atom or —N (R) - (where R represents a hydrogen atom or an acyl group and “*” represents a binding site)) and R represents a pyridyl, indazolyl, phenyl, pyrazolopyridyl, benzisoxazolyl, pyrimidinyl or quinolinyl ny, each of which optionally contains at least one zamestitel.2. The nicotinamide derivative or its salt according to claim 1, wherein R is a substituent of formula (II-2), (III-2) or (IV-2): [Formula 3] (where R, R, R, n and X are the same definitions as specified in paragraph 1) .3. The nicotinamide derivative or its salt according to claim 1 or 2, wherein R represents a hydrogen atom or a C 1-6 alkyl, C 1-6 cycloalkyl, phenyl, pyridyl or thienyl group, each of which optionally contains at least one substituent selected from the group of substituents and C1-6 alkyl, C1-6 cycloalkyl, C1-6 alkoxy, C1-6 alkyl1. Производное никотинамида, представленное следующей формулой (I), или его соль:[Формула 1]гдеRпредставляет собой заместитель формулы (II-1), (III-1) или (IV-1):[Формула 2](гдеRпредставляет собой атом водорода или Cалкильную, Cциклоалкильную, фенильную, пиридильную или тиенильную группу, каждая из которых необязательно содержит по меньшей мере один заместитель,Rпредставляет собой атом водорода, C
