"Secret of My Heart" is a song by Japanese singer songwriter Mai Kuraki, taken from her debut album Delicious Way (2000).

It was released on April 26, 2000, and peaked at number two on the Oricon Weekly Singles Chart.

[1] "Secret of My Heart" was certificated Million by Recording Industry Association of Japan and won the Japan Gold Disc Award for Song of the Year.

[2] "Secret of My Heart" debuted at number two on the Oricon Weekly Singles Chart with 410,550 physical copies sold.

"Secret of My Heart" became the singer's second best-selling song behind "Love, Day After Tomorrow" (1999) and has been certificated Million for physical sales and Gold for digital sales by Recording Industry Association of Japan.