A wind turbine power generating apparatus for generating electric power from wind energy, comprising: a wind turbine rotor including at least one blade; a pitch drive part for changing a pitch angle of the at least one blade; a generator configured to be driven by rotational energy of the wind turbine rotor; a circuit breaker for switching a connection state of the generator with respect to a utility grid; and a controller for controlling the wind turbine power generating apparatus, the controller including a pitch control part configured to control the pitch drive part in a constant rotation-speed control mode for limiting a change rate of the pitch angle to be not greater than an upper limit value, before a rotation speed of the wind turbine rotor reaches a target rotation speed corresponding to a connection rotation speed of the generator, and maintaining the rotation speed of the wind turbine rotor at the target rotation speed, and a connection-command generation part configured to provide the circuit breaker with a connection command to connect the generator to the utility grid while the rotation speed of the wind turbine rotor is maintained at the target rotation speed, wherein the pitch control part is configured to control the pitch drive part so that the pitch angle changes in accordance with a predetermined pitch schedule from when the wind turbine rotor is stopped until when the rotation speed reaches a first rotation-speed threshold value smaller than the target rotation speed, and control the pitch drive part in the constant rotation-speed control mode when the rotation speed reaches the first rotation-speed threshold value or higher, wherein the pitch schedule is configured such that the pitch angle is changed at at least one pitch rate toward a fine side to reach a standby pitch angle, and when the pitch angle reaches the standby pitch angle, the pitch angle is maintained to be constant at the standby pitch angle until the rotation speed of the wind turbine rotor reaches a second rotation-speed threshold value smaller than the first rotation-speed threshold value, characterized in that the pitch schedule is configured such that the pitch angle is changed at at least one pitch rate toward the fine side from the standby pitch angle when the rotation speed of the wind turbine rotor reaches the second rotation-speed threshold value. a wind turbine rotor including at least one blade; a pitch drive part for changing a pitch angle of the at least one blade; a generator configured to be driven by rotational energy of the wind turbine rotor; a circuit breaker for switching a connection state of the generator with respect to a utility grid; and a controller for controlling the wind turbine power generating apparatus, the controller including a pitch control part configured to control the pitch drive part in a constant rotation-speed control mode for limiting a change rate of the pitch angle to be not greater than an upper limit value, before a rotation speed of the wind turbine rotor reaches a target rotation speed corresponding to a connection rotation speed of the generator, and maintaining the rotation speed of the wind turbine rotor at the target rotation speed, and a connection-command generation part configured to provide the circuit breaker with a connection command to connect the generator to the utility grid while the rotation speed of the wind turbine rotor is maintained at the target rotation speed, wherein the pitch control part is configured to a pitch control part configured to control the pitch drive part in a constant rotation-speed control mode for limiting a change rate of the pitch angle to be not greater than an upper limit value, before a rotation speed of the wind turbine rotor reaches a target rotation speed corresponding to a connection rotation speed of the generator, and maintaining the rotation speed of the wind turbine rotor at the target rotation speed, and a connection-command generation part configured to provide the circuit breaker with a connection command to connect the generator to the utility grid while the rotation speed of the wind turbine rotor is maintained at the target rotation speed, wherein the pitch control part is configured to control the pitch drive part so that the pitch angle changes in accordance with a predetermined pitch schedule from when the wind turbine rotor is stopped until when the rotation speed reaches a first rotation-speed threshold value smaller than the target rotation speed, and control the pitch drive part in the constant rotation-speed control mode when the rotation speed reaches the first rotation-speed threshold value or higher, wherein the pitch schedule is configured such that the pitch angle is changed at at least one pitch rate toward a fine side to reach a standby pitch angle, and when the pitch angle reaches the standby pitch angle, the pitch angle is maintained to be constant at the standby pitch angle until the rotation speed of the wind turbine rotor reaches a second rotation-speed threshold value smaller than the first rotation-speed threshold value, characterized in that the pitch schedule is configured such that the pitch angle is changed at at least one pitch rate toward the fine side from the standby pitch angle when the rotation speed of the wind turbine rotor reaches the second rotation-speed threshold value.