An object of the present invention is to provide rounded zinc peroxide particles having a large particle diameter, the rounded zinc peroxide particles having excellent performance because they have an average particle diameter of 0.04 µm or more, a small aspect ratio and a shape close to a spherical shape； rounded zinc oxide particles which are obtained by calcinating the rounded zinc peroxide particles and which have a small aspect ratio and a sharp particle size distribution； a method for production thereof； and a cosmetic and a heat releasing filler each containing the rounded zinc oxide particles. Provided are rounded zinc peroxide particles having an average particle diameter of 0. 04 µm or more and an aspect ratio of 2.0 or less, and rounded zinc oxide particles which are obtained by thermally decomposing the rounded zinc peroxide particles and which have an average particle diameter of 0.04 µm or more and an aspect ratio of 2.0 or less.[과제] 평균 입자경이 0.04㎛ 이상이며, 어스펙트비가 작고, 구상 형상에 가깝다는 점에서 우수한 성능을 갖는 입자경이 큰 둥근 형상 과산화아연 입자, 그것을 소성해서 얻어지는 어스펙트비가 작고, 입도 분포가 샤프한 둥근 형상 산화아연 입자, 그들의 제조 방법, 및 그러한 둥근 형상 산화아연 입자를 배합한 화장료, 방열성 필러를 제공한다.[해결 수단] 평균 입자경이 0.04㎛ 이상, 어스펙트비가 2.0 이하인 둥근 형상 과산화아연 입자 및 당해 둥근 형상 과산화아연 입자를 열분해함에 의해 얻어진 평균 입자경이 0.04㎛ 이상, 어스펙트비가 2.0 이하인 둥근 형상 산화아연 입자.
