The invention provides an information acquisition system and device, a shopping assistance system, and a shopping assistance method. The invention aims to improve the reliability of reading of information of RF tags adhered on articles and read the information of the RF tags in a short time. The information acquisition system includes an inner wall, an outer wall, and an antenna (31). The inner wall includes a reflective layer (225) which reflects a radio wave. A reading space (27) is located on an inner side of the reflective layer (225). Reading of tag information from an RF tag attached toan item is performed in the reading space (27). The outer wall is disposed on an opposite side of the inner wall from the reading space (27). The antenna (31) is configured to output the radio wave toward the reading space (27) in order to communicate with the RF tag. Between the inner wall and the outer wall, a peripheral space is provided. The reflective layer (225) of the inner wall has a hole(261-266). The hole penetrates through the reflective layer (225) in a thickness direction of the reflective layer.