This study aims to describe the illocutionary speech acts contained in adverb chotto usage along with the function of the adverb chotto in Japanese. Adverb chotto is a word that is often used in Japanese conversation and then every language user cannot be separated from illocutionary speech acts. This study used a qualitative descriptive method with a speech act theoretical approach. Sources of research data are taken from the adverb chotto in Japanese drama, Hana ni Keda Mono and Hana Nochi Hare: Hanadan Next Season. Based on the study result, there are 30 Japanese datas containing adverb chotto, 9 datas are assertive ilocutionary acts, 15 datas are direct illocutionary acts, 2 datas are commissive illocutionary acts, 3 datas are expressive illocutionary acts, and 1 datas is declaration illocutionary acts. The study result also found 8 adverb chotto functions, there are refine negative expressions, refine expressions of rejection, refine the expression of a negative state, state the boundary of a situation, refine the expression of deman, attract people's attention, refine the tone of voice and expression of judgment.