Based on the channel models specified by the 3GPP, this study provides distributions of the cumulative angular power spectrum (cAPS) for base stations in the indoor-office (InO) and indoor-factory (InF) scenarios. The cAPS is obtained using Monte Carlo simulations with 5000 randomly distributed user equipment per studied scenario. The cAPS in the elevation direction is fitted by the Rayleigh distribution and Gaussian distribution for the InO and InF scenarios, respectively. The effects of the room size and the frequency dependency from sub-6 GHz to 39 GHz are also investigated. The obtained distributions of the cAPS can offer insights into antenna design and placement of indoor base stations.