A method of producing a high-infectivity-titer and high-purity parvovirus which does not need a helper virus for virus replication and grows autonomously in a host cell, comprising: (a) a step of preliminarily calculating, every 24 hours, a time-dependent change of a cell density of a culture substrate when host cells are infected with a parvovirus for each cell density (A) when infecting virus; (b) a step of determining, based on the time-dependent change of a cell density calculated preliminarily in the step (a), (b1) time (T max ) from infection to peak time of the time-dependent change of a cell density, (b2) a cell density (B max ) at T max and A 1 which is A that satisfies the following equation , (b3) the maximum (A max ) of the cell density A 1 when infecting virus, and (b4) A 2 that satisfies the following equation ; B max / A 1 > 1.2 A max ≥ A 2 ≥ A max / 10 (c) a step of inoculating a seed virus of the parvovirus into the culture substrate containing host cells having the cell density A 2 when infecting virus determined in (b4) of the step (b) and a serum medium to give a multiplicity of infection (MOI) of from 0.001 to 0.1; (d) a step of culturing a cultured product containing the host cells and the parvovirus obtained in the step (c) for a time period of T max or more to less than (T max + 48) hours, wherein T max is determined in (b1) of the step (b); (e) a step of replacing a culture supernatant obtained in the step (d) with a serum-free medium and culturing for 12 hours or more; and (f) a step of collecting the parvovirus-containing culture supernatant obtained by culturing in the step (e); wherein in the step (b), when A satisfying the equation is absent, the steps (a) and (b) are performed again by using another cell density A when infecting virus. (a) a step of preliminarily calculating, every 24 hours, a time-dependent change of a cell density of a culture substrate when host cells are infected with a parvovirus for each cell density (A) when infecting virus; (b) a step of determining, based on the time-dependent change of a cell density calculated preliminarily in the step (a), (b1) time (T max ) from infection to peak time of the time-dependent change of a cell density, (b2) a cell density (B max ) at T max and A 1 which is A that satisfies the following equation , (b3) the maximum (A max ) of the cell density A 1 when infecting virus, and (b4) A 2 that satisfies the following equation ; B max / A 1 > 1.2 A max ≥ A 2 ≥ A max / 10 (b1) time (T max ) from infection to peak time of the time-dependent change of a cell density, (b2) a cell density (B max ) at T max and A 1 which is A that satisfies the following equation , (b3) the maximum (A max ) of the cell density A 1 when infecting virus, and (b4) A 2 that satisfies the following equation ; B max / A 1 > 1.2 A max ≥ A 2 ≥ A max / 10 (c) a step of inoculating a seed virus of the parvovirus into the culture substrate containing host cells having the cell density A 2 when infecting virus determined in (b4) of the step (b) and a serum medium to give a multiplicity of infection (MOI) of from 0.001 to 0.1; (d) a step of culturing a cultured product containing the host cells and the parvovirus obtained in the step (c) for a time period of T max or more to less than (T max + 48) hours, wherein T max is determined in (b1) of the step (b); (e) a step of replacing a culture supernatant obtained in the step (d) with a serum-free medium and culturing for 12 hours or more; and (f) a step of collecting the parvovirus-containing culture supernatant obtained by culturing in the step (e); <EOS>