Abstract: A shaft sealing device (80) that partitions a high-pressure zone and a low-pressure zone from each other in a fluid machine has an elastic member (86) including a seal portion (88) that is brought into sliding contact with a seat face of a contact-target member that is either a rotary shaft (60) or a casing (12), and a case (82) that supports the elastic member (86). The elastic member (86) has a first elastic portion that continues to a high-pressure side boundary of the seal portion (88), which is located in the high-pressure zone side, and a second elastic portion that continues to a low-pressure side boundary of the seal portion (88), which is located in the low-pressure zone side. The case (82) restrains regions of the first and second elastic portions, the regions being located away from the seal portion (88).