A start-up method of a wind turbine generator, comprising: a step of increasing a pitch angle of a wind turbine blade from a feather pitch angle to a fine pitch angle, the start-up method being characterized in that the step of increasing said pitch angle includes steps of: determining based on first to n-th pitch angles (n ≥ 2) greater than said feather pitch angle and smaller than said fine pitch angle and first to n-th judgment speeds associated with said first to n-th pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, exceeds said i-th judgment speed when said pitch angle reaches the i-th rotational speed out of said first to n-th pitch angles, the first to n-th pitch angles and the first to n-th judgment speeds being stored in a storage unit; decreasing said pitch angle to said (i-1)-th pitch angle or said feather pitch angle in a case that said control target rotational speed does not exceed said i-th judgment speed when said pitch angle reaches the i-th pitch angle; and increasing said pitch angle to said (i+1)-th pitch angle or said fine pitch angle in a case that said control target rotational speed exceeds said i-th judgment speed when said pitch angle reaches said i-th pitch angle. a step of increasing a pitch angle of a wind turbine blade from a feather pitch angle to a fine pitch angle, the start-up method being characterized in that the step of increasing said pitch angle includes steps of: determining based on first to n-th pitch angles (n ≥ 2) greater than said feather pitch angle and smaller than said fine pitch angle and first to n-th judgment speeds associated with said first to n-th pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, exceeds said i-th judgment speed when said pitch angle reaches the i-th rotational speed out of said first to n-th pitch angles, the first to n-th pitch angles and the first to n-th judgment speeds being stored in a storage unit; decreasing said pitch angle to said (i-1)-th pitch angle or said feather pitch angle in a case that said control target rotational speed does not exceed said i-th judgment speed when said pitch angle reaches the i-th pitch angle; and increasing said pitch angle to said (i+1)-th pitch angle or said fine pitch angle in a case that said control target rotational speed exceeds said i-th judgment speed when said pitch angle reaches said i-th pitch angle. determining based on first to n-th pitch angles (n ≥ 2) greater than said feather pitch angle and smaller than said fine pitch angle and first to n-th judgment speeds associated with said first to n-th pitch angles, respectively, whether a control target rotational speed, which is a wind turbine speed or generator speed, exceeds said i-th judgment speed when said pitch angle reaches the i-th rotational speed out of said first to n-th pitch angles, the first to n-th pitch angles and the first to n-th judgment speeds being stored in a storage unit; decreasing said pitch angle to said (i-1)-th pitch angle or said feather pitch angle in a case that said control target rotational speed does not exceed said i-th judgment speed when said pitch angle reaches the i-th pitch angle; and increasing said pitch angle to said (i+1)-th pitch angle or said fine pitch angle in a case that said control target rotational speed exceeds said i-th judgment speed when said pitch angle reaches said i-th pitch angle.