The following is a list of number-one singles on the Billboard Japan Hot 100 chart in 2019.
| Issue date | Song | Artist(s) | Ref. |
|---|---|---|---|
| January 7 | "Lemon" | Kenshi Yonezu | [1] |
| January 14 | [2] | ||
| January 21 | [3] | ||
| January 28 | [4] | ||
| February 4 | [5] | ||
| February 11 | "Homechigirist" | Johnny's West | [6] |
| February 18 | "Kimi o Daisuki da" | Kis-My-Ft2 | [7] |
| February 25 | "Kaze o Matsu" | STU48 | [8] |
| March 4 | "Tokonoma Seiza Musume" | NMB48 | [9] |
| March 11 | "Kuroi Hitsuji" | Keyakizaka46 | [10] |
| March 18 | "Crystal" | Kanjani Eight | [11] |
| March 25 | "Jiwaru Days" | AKB48 | [12] |
| April 1 | "Uchōten Shooter" | Matsuri Nine | [13] |
| April 8 | "Kyun" | Hinatazaka46 | [14] |
| April 15 | "Kimi o Matteru" | King & Prince | [15] |
| April 22 | "Ishi" | HKT48 | [16] |
| April 29 | "Otona Survivor" | Last Idol | [17] |
| May 6 | "Ame Nochi Hare" | Johnny's West | [18] |
| May 13 | "Marigold" | Aimyon | [19] |
| May 20 | "Dark Knight" | One n' Only | [20] |
| May 27 | "Rain" | Kazuya Kamenashi | [21] |
| June 3 | "Lucky-Unlucky" | Hey! Say! JUMP | [22] |
| June 10 | "Sing Out!" | Nogizaka46 | [23] |
| June 17 | "Spirits of the Sea" | Kenshi Yonezu | [24] |
| June 24 | "Top Gun" | NEWS | [25] |
| July 1 | "Change" | Tomohisa Yamashita | [26] |
| July 8 | "Buenos Aires" | Iz*One | [27] |
| July 15 | "Lights" | BTS | [28] |
| July 22 | "Hands Up" | Kis-My-Ft2 | [29] |
| July 29 | "Do Re Mi Sol La Si Do" | Hinatazaka46 | [30] |
| August 5 | "Breakthrough" | Twice | [31] |
| August 12 | "Daisuki na Hito" | STU48 | [32] |
| August 19 | "Scarlet" | Sandaime J Soul Brothers featuring Afrojack | [33] |
| August 26 | "Bokō o Kaere!" | NMB48 | [34] |
| September 2 | "Fanfare!" | Hey! Say! JUMP | [35] |
| September 9 | "Koi-Wazurai" | King & Prince | [36] |
| September 16 | "Yoake Made Tsuyogaranakutemoii" | Nogizaka46 | [37] |
| September 23 | "Uma to Shika" | Kenshi Yonezu | [38] |
| September 30 | "Sustainable" | AKB48 | [39] |
| October 7 | "Vampire" | Iz*One | [40] |
| October 14 | "Konna ni Suki ni Natchatte Ii no?" | Hinatazaka46 | [41] |
| October 21 | "Big Shot!!" | Johnny's West | [42] |
| October 28 | "Pretender" | Official Hige Dandism | [43] |
| November 4 | "Kirin no Ko" | Sexy Zone | [44] |
| November 11 | "Zurui yo Zurui ne" | =Love | [45] |
| November 18 | "Hatsukoi Shijō Shugi" | NMB48 | [46] |
| November 25 | "Edge of Days" | Kis-My-Ft2 | [47] |
| December 2 | "Pretender" | Official Hige Dandism | [48] |
| December 9 | "Tomo yo" | Kanjani Eight | [49] |
| December 16 | "Hikari no Kehai" | KinKi Kids | [50] |
| December 23 | "Pretender" | Official Hige Dandism | [51] |
| December 30 | [52] |