An transformer inrush current restraining control equipment, adapted to control a breaker closing timing that is installed between a three-phase transformer and a power system source-side and is connected to both of them, said equipment comprises: a voltage measuring unit adapted to measure three-phase voltages of said three-phase transformer and three-phase voltages of said system power system source-side; a core-flux calculating unit adapted to calculate fluxes in the three-phase transformer cores by integration of the three-phase voltages of said three-phase transformer which have been measured by the said voltage measuring unit (1 a); a true residual fluxes timing calculating unit adapted to measure the true residual fluxes timing by utilizing the three phase voltage values of said three-phase transformer measured by said voltage measuring unit, and that is measured as the timing when the three-phase transient voltages simultaneously converge to zero values or disappear at the end of the transient phenomenon just after said breaker tripping; a true residual flux calculating unit adapted to calculate the fluxes values in the three-phase cores of the transformer obtained as the flux values at the instant moment of the true residual fluxes timing, and memorize them as the true residual fluxes which have been calculated by said core-flux calculating unit; a breaker closing phase angular timing calculating unit adapted to calculate the appropriate phase angular timing of the breaker closing operation by utilizing the true residual fluxes values calculated by said true residual flux calculating unit; and a breaker closing phase angular timing controlling unit adapted to control the breaker closing by utilizing the three phase voltages of said power system source-side that are measured by said voltage measuring unit and the breaker closing phase angular timing that have been calculated by said breaker closing phase angular calculating unit, charactrtised in that said breaker closing phase angular timing calculating unit comprises: a phasor value calculating section adapted to calculate phasor values φ r of a vector equilateral triangle of the true residual fluxes of said respective phases, which have been calculated by said true residual flux calculating unit by utilizing said true residual fluxes (φ a (θ open1), φ b (θ open1), φ c (θ open1)) and on a following equation: φ r = 2 / 3 × φ a θ open 1 2 + φ b θ open 1 2 + φ c θ open 1 2 and a breaker closing phase angle determining section adapted to calculate said breaker closing phase angle 0 close (θ a, θ b, θ c) by utilizing said true residual fluxes (φ a (θ open1), φ b (θ open1), φ c (θ open1)) which have been calculated by said true residual flux calculating unit, the phasor value φ r which has been calculated by said phasor value calculating section, and a set of following equations: θ a = sin -1 φ a θ open 1 / φ r θ b = sin -1 φ b θ open 1 / φ r θ c = sin -1 φ c θ open 1 / φ r. a voltage measuring unit adapted to measure three-phase voltages of said three-phase transformer and three-phase voltages of said system power system source-side; a core-flux calculating unit adapted to calculate fluxes in the three-phase transformer cores by integration of the three-phase voltages of said three-phase transformer which have been measured by the said voltage measuring unit (1 a); a true residual fluxes timing calculating unit adapted to measure the true residual fluxes timing by utilizing the three phase voltage values of said three-phase transformer measured by said voltage measuring unit, and that is measured as the timing when the three-phase transient voltages simultaneously converge to zero values or disappear at the end of the transient phenomenon just after said breaker tripping; a true residual flux calculating unit adapted to calculate the fluxes values in the three-phase cores of the transformer obtained as the flux values at the instant moment of the true residual fluxes timing, and memorize them as the true residual fluxes which have been calculated by said core-flux calculating unit; a breaker closing phase angular timing calculating unit adapted to calculate the appropriate phase angular timing of the breaker closing operation by utilizing the true residual fluxes values calculated by said true residual flux calculating unit; and a breaker closing phase angular timing controlling unit adapted to control the breaker closing by utilizing the three phase voltages of said power system source-side that are measured by said voltage measuring unit and the breaker closing phase angular timing that have been calculated by said breaker closing phase angular calculating unit, charactrtised in that a phasor value calculating section adapted to calculate phasor values φ r of a vector equilateral triangle of the true residual fluxes of said respective phases, which have been calculated by said true residual flux calculating unit by utilizing said true residual fluxes (φ a (θ open1), φ b (θ open1), φ c (θ open1)) and on a following equation: φ r = 2 / 3 × φ a θ open 1 2 + φ b θ open 1 2 + φ c θ open 1 2 and a breaker closing phase angle determining section adapted to calculate said breaker closing phase angle 0 close (θ a, θ b, θ c) by utilizing said true residual fluxes (φ a (θ open1), φ b (θ open1), φ c (θ open1)) which have been calculated by said true residual flux calculating unit, the phasor value φ r which has been calculated by said phasor value calculating section, and a set of following equations: θ a = sin -1 φ a θ open 1 / φ r θ b = sin -1 φ b θ open 1 / φ r θ c = sin -1 φ c θ open 1 / φ r.