The PreHeart (プリハート PuriHāto?) is the main transformation device used by the Cures in HUGtto! Pretty Cure. To activate the transformation, they need to insert their Mirai Crystal on top of it and shout out the phrase "Heart Kiratto!". They are also used for the Cures' first solo attacks.
The PreHeart resembles a pink cellphone with a red and gold button on top and a black screen. The screen is bordered by different shaped and cut gems with three connected hearts on the upper right side and a red heart-shaped button on the bottom right corner. Toward the bottom part of the screen are two hexagon-shaped buttons, one blue and one yellow, and a round pink one that also resembles a gem. Whenever the Cures transform or attack, a glowing heart would appear, which can change into various colors depending on what part of the transformation they are up to. The bottom part has a golden gem with a string of pink ones lining the bottom of it. When a Mirai Crystal is inserted at the top, the bottom part is flipped to the side, making the device heart-shaped. In that form, the left side of it also has three connected hearts and a gem.
The PreHeart can be used for the Cures to transform whenever they insert their Mirai Crystal onto the top. It is also used during their solo attacks, usually waving their hand over the screen to initiate it. They can also be used to call other PreHeart holders.
- Cure Yell uses the PreHeart in Heart Kiratto!, along with the Mirai Crystal Pink. She also uses the PreHeart and the Mirai Crystal Pink in Heart For You!
- Cure Ange uses the PreHeart in Heart Kiratto!, along with the Mirai Crystal Blue. She also uses it for Heart Feather!, along with the Mirai Crystal Blue or Mirai Crystal Navy.
- Cure Etoile uses the PreHeart in Heart Kiratto!, along with the Mirai Crystal Yellow. She also uses it for Heart Star!, along with the Mirai Crystal Yellow or Mirai Crystal Orange.
- Cure Macherie uses the PreHeart in Heart Kiratto!, alongside Cure Amour and with the Mirai Crystal Red. She also uses the PreHeart and the Mirai Crystal Red in Heart Song!
- Cure Amour uses the PreHeart in Heart Kiratto!, alongside Cure Macherie and with the Mirai Crystal Purple. She also uses the PreHeart and the Mirai Crystal Purple in Heart Dance!
- In episode 10, it is shown that if the owner of a PreHeart is having serious doubts about her future or purpose, then it doesn't work.
- Even though there are 5 Cures, only 4 PreHearts are available initially. However, because of Ruru and Emiru's strong desire to become Pretty Cures, Mother Heart appears and creates an extra PreHeart.