This is a posable action figure from the figma series.
From the Good Smile Company website:
From the anime "THE IDOLM@STER" comes a figma of Chihaya Kisaragi wearing her IDOLM@STER Million Live outfit! Using the smooth yet posable joints of figma, you can act out a variety of different scenes. A flexible plastic is used for important areas, allowing proportions to be kept without compromising posability. She comes with three expressions including a gentle smile, a serious singing face and an embarrassed face. Optional parts include a microphone, speaker and lighting equipment. A special di:stage unit is included to create a stage for her to perform on. An articulated figma stand is included, which allows various poses to be taken.