An expansion valve (10, 10A, 10B) comprising: a valve main body (2, 2D) comprising a first flow channel, a valve chamber and a valve seat, wherein the first flow channel is a supply-side flow channel for supplying a fluid to the valve chamber, and the first flow channel and the valve chamber are connected via a connection path having a smaller diameter than the first flow channel; a valve body (3, 3A, 3B) configured to limit passage of a fluid by being seated on the valve seat and allow passage of the fluid by separating from the valve seat; a coil spring configured to urge the valve body (3, 3A, 3B) toward the valve seat; and an actuation rod configured to press the valve body (3, 3A, 3B) toward a direction separating from the valve seat against an urging force applied from the coil spring, wherein the valve chamber comprises a cylindrical inner wall (24, 24A, 24B, 24D) being connected to the valve seat, the valve body (3, 3A, 3B) comprises a contact portion (31, 31A, 31B) configured to be seated on the valve seat and a body portion (32, 32A, 32B, 32D) having a tubular shape facing the inner wall (24, 24A, 24B, 24D), in a cross section taken in a direction orthogonal to an axis of the valve body (3, 3A, 3B), a shape of an inner circumference of the inner wall (24, 24A, 24B, 24D) differs from a shape of an outer circumference of the body portion (32, 32A, 32B, 32D), so that a space through which the fluid, during operation of the expansion valve (10, 10A, 10B), passes is formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D), and the inner circumference of the inner wall (24, 24A, 24B, 24D) and the outer circumference of the body portion (32, 32A, 32B, 32D) are partially slidably in contact with each other, characterized in that the expansion valve (10, 10A, 10B) is configured such that, during operation of the expansion valve (10, 10A, 10B), the fluid is supplied through the connection path to a portion of the valve chamber that is on the opposite side from the valve seat with respect to the inner wall (24, 24A, 24B, 24D) opposing the body portion (32, 32A, 32B, 32D) and is further guided along plane surfaces along the axial length of the body portion (32, 32A, 32B, 32D) through a relatively narrow gap formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D) such that bubbles in the fluid are gradually collapsed, and the expansion valve (10, 10A, 10B) is further configured such that, during operation, the fluid passes the valve seat after passing through the relatively narrow gap formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D). a valve main body (2, 2D) comprising a first flow channel, a valve chamber and a valve seat, wherein the first flow channel is a supply-side flow channel for supplying a fluid to the valve chamber, and the first flow channel and the valve chamber are connected via a connection path having a smaller diameter than the first flow channel; a valve body (3, 3A, 3B) configured to limit passage of a fluid by being seated on the valve seat and allow passage of the fluid by separating from the valve seat; a coil spring configured to urge the valve body (3, 3A, 3B) toward the valve seat; and an actuation rod configured to press the valve body (3, 3A, 3B) toward a direction separating from the valve seat against an urging force applied from the coil spring, wherein the valve chamber comprises a cylindrical inner wall (24, 24A, 24B, 24D) being connected to the valve seat, the valve body (3, 3A, 3B) comprises a contact portion (31, 31A, 31B) configured to be seated on the valve seat and a body portion (32, 32A, 32B, 32D) having a tubular shape facing the inner wall (24, 24A, 24B, 24D), in a cross section taken in a direction orthogonal to an axis of the valve body (3, 3A, 3B), a shape of an inner circumference of the inner wall (24, 24A, 24B, 24D) differs from a shape of an outer circumference of the body portion (32, 32A, 32B, 32D), so that a space through which the fluid, during operation of the expansion valve (10, 10A, 10B), passes is formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D), and the inner circumference of the inner wall (24, 24A, 24B, 24D) and the outer circumference of the body portion (32, 32A, 32B, 32D) are partially slidably in contact with each other, characterized in that the expansion valve (10, 10A, 10B) is configured such that, during operation of the expansion valve (10, 10A, 10B), the fluid is supplied through the connection path to a portion of the valve chamber that is on the opposite side from the valve seat with respect to the inner wall (24, 24A, 24B, 24D) opposing the body portion (32, 32A, 32B, 32D) and is further guided along plane surfaces along the axial length of the body portion (32, 32A, 32B, 32D) through a relatively narrow gap formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D) such that bubbles in the fluid are gradually collapsed, and the expansion valve (10, 10A, 10B) is further configured such that, during operation, the fluid passes the valve seat after passing through the relatively narrow gap formed between the inner wall (24, 24A, 24B, 24D) and the body portion (32, 32A, 32B, 32D).