This study aims to analyse the use of code-switching in the song lyrics from the album Ambition by the Japanese band One Ok Rock. Adopting a qualitative research method, this study describes and interprets the data comprehensively. Sociolinguistics serves as the theoretical framework to investigate the meanings, types, and functions of code-switching present in the lyrics. The analysis identifies three types of code-switching in the album: tag-switching, intra-sentential switching, and intersentential switching. Furthermore, four functions of code-switching are observed: expressive, phatic, metalinguistic, and poetic functions. The findings reveal a total of 34 occurrences of code-switching, consisting of 18 instances categorized by type and 16 instances by function. These results contribute to a deeper understanding of the linguistic strategies employed in the album and their sociolinguistic implications.