This study aims to reveal prosodic features related to next speaker selection in spontaneous Japanese conversation. A turn-taking system in the field of conversation analysis in sociology was proposed as a systematic basis of speaker-change for conversation. In a previous study, we demonstrated that the prosody of Japanese utterance is relevant to one component of the system, namely, a turn-constructional component. However, it is unclear whether the prosody is also relevant to another component, that is, a turn-allocation component. In this paper, while focusing on next speaker selection as one of the turn-allocation techniques, we investigated relationships between the prosodic features and types of next speaker selection in utterances. The results showed that the difference of the F0s between the penultimate and the final accent phrase in utterance differs whether the current utterance selects the next speaker. Also, the power and the mora duration at the final accent phrase differ whether the current speaker does self-selection in the current utterance. These suggest that the prosodic features are clues for selecting the next speaker in the current utterance.