Valve seat member, valve, and shock absorber

A valve seat member having a seat surface, comprising:

• a main body portion having a port, the port opening at a one end portion of the main body portion;
• a first seat projecting out from the one end portion of the main body portion, the first seat being spaced apart from the opening of the port;
• a second seat projecting out from the one end portion of the main body portion, surrounding the opening of the port, and having two opposite ends in a circumferential direction of the main body portion, each of the two opposite ends of the second seat being connected to the first seat;
• an island portion disposed within an area surrounded by the first seat and the second seat and at a position closer to the first seat than is the opening such that a hollow space is formed between the island portion and the first seat;
• and
• a passage formed in the island portion, and being configured to allow communication between the port and the hollow space, wherein
• the island portion projects out from the one end portion of the main body portion, and has a tip end that is disconnected and spaced apart from each of the first seat and the second seat at the seat surface.