To provide an accumulator capable of suppressing the occurrence of abnormal noise accompanying the generation of air bubbles to the minimum, in the accumulator provided with a gas-liquid separation member.

An accumulator 1 includes a tank main body 2 comprising a cylindrical barrel body 3 with an upper end opening and a header 4 connected to an opening part of the barrel body. Therein, a coolant inflow pore 8 and a coolant outflow pore 9 which are opened in the vertical direction are disposed on the header, an inner pipe 6 is connected to the coolant outflow pore, an outer pipe 5 is arranged on the outside of the inner pipe so as to form a double pipe, a gas-liquid separation member 16 to which a coolant inflow port of the header is opposed is installed fixedly on an upper space position in the barrel body, and an extension member 20 is disposed so as to be extended horizontally from the outer pipe integrally on a position in the proximity to the lower side of the gas-liquid separation member and a desiccant agent bag 7 is suspended and retained onto the extension member. At least two cut-off grooves 7c are disposed on the desiccant agent bag and an arm part 20a of the extension member is inserted to the cut-off grooves and can be suspended and retained.