A needle threading device comprising: a needle receiving mechanism having a needle insertion hole for receiving a needle therein and a thread insertion slit for receiving a thread therein; the thread insertion slit extending at an angle relative to the needle insertion hole and communicating with the needle insertion hole; a threading mechanism provided with a threader pin and pivotally supported by the needle receiving mechanism so as to be pivotable between a first position and a second position different from the first position; the threader pin enabling the thread in the thread insertion slit to pass through an eye of the needle in the needle insertion hole when the threading mechanism is pivoted to the second position from the first position; and a first biasing member urging the threading mechanism to the first position; characterized in that the needle threading device includes an operating member causing the threading mechanism to be pivoted to the second position against an action of the first biasing member; and a second biasing member urging the operating member and the threading mechanism in a direction in which they are spaced away from each other; wherein when the operating member is operated so as to be moved in a direction in which it approaches the threading mechanism, the threading mechanism is pushed by an action of the second biasing member to be pivoted to the second position against the action of the first biasing member; and when the threading mechanism is pivoted toward the second position and the threader pin is abutted against the needle in the needle insertion hole, the pivotal movement of the threading mechanism to the second position is stopped and the operating member approaches the treading mechanism against the action of the second biasing member. a needle receiving mechanism having a needle insertion hole for receiving a needle therein and a thread insertion slit for receiving a thread therein; the thread insertion slit extending at an angle relative to the needle insertion hole and communicating with the needle insertion hole; a threading mechanism provided with a threader pin and pivotally supported by the needle receiving mechanism so as to be pivotable between a first position and a second position different from the first position; the threader pin enabling the thread in the thread insertion slit to pass through an eye of the needle in the needle insertion hole when the threading mechanism is pivoted to the second position from the first position; and a first biasing member urging the threading mechanism to the first position; characterized in that the needle threading device includes an operating member causing the threading mechanism to be pivoted to the second position against an action of the first biasing member; and a second biasing member urging the operating member and the threading mechanism in a direction in which they are spaced away from each other; wherein when the operating member is operated so as to be moved in a direction in which it approaches the threading mechanism, the threading mechanism is pushed by an action of the second biasing member to be pivoted to the second position against the action of the first biasing member; and when the threading mechanism is pivoted toward the second position and the threader pin is abutted against the needle in the needle insertion hole, the pivotal movement of the threading mechanism to the second position is stopped and the operating member approaches the treading mechanism against the action of the second biasing member.