A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.