A pipe connector which is configured to connect a pipe to another, comprising: a connector body having an insertion hole into which the pipe is insertable, the pipe having an outer periphery having an end side formed with a flange; a retainer (2; 50) having a locking portion configured to be attached to the connector body, a pair of locking legs (26; 51) which are moved into the insertion hole of the connector body from a direction intersecting an axial direction of the connector body, the locking legs (26; 51) being positioned in the insertion hole so as to protrude, before insertion of the pipe, the locking legs (26; 51) being elastically flexed so as to retreat outward from the insertion hole with pass of the flange thereby to allow the flange to pass through the insertion hole, the locking legs (26; 51) being elastically returned to lock a rear part of the flange, thereby retaining the pipe, and a release operation portion (28; 54) displacing the locking legs (26; 51) in a direction such that the pipe is released from a retained state; and a checker (3; 60) which is locked to the connector body so as to assume a preliminary holding position and released from a locked state at the preliminary holding position thereby to be movable to a detection position when the pipe is inserted into the insertion hole thereby to assume a normal position, wherein the checker (3; 60) is provided with a cover (34; 64) configured to cover the release operation portion (28; 54) of the retainer (2; 50) when the checker (3; 60) assumes the detection position, characterized in that the checker (3; 60) is formed with a pressing piece which is located rearward in the insertion direction of the pipe relative to the locking legs (26; 51) when the checker (3; 60) assumes the detection position, thereby preventing the locking legs (26; 51) from being flexed rearward. a connector body having an insertion hole into which the pipe is insertable, the pipe having an outer periphery having an end side formed with a flange; a retainer (2; 50) having a locking portion configured to be attached to the connector body, a pair of locking legs (26; 51) which are moved into the insertion hole of the connector body from a direction intersecting an axial direction of the connector body, the locking legs (26; 51) being positioned in the insertion hole so as to protrude, before insertion of the pipe, the locking legs (26; 51) being elastically flexed so as to retreat outward from the insertion hole with pass of the flange thereby to allow the flange to pass through the insertion hole, the locking legs (26; 51) being elastically returned to lock a rear part of the flange, thereby retaining the pipe, and a release operation portion (28; 54) displacing the locking legs (26; 51) in a direction such that the pipe is released from a retained state; and a checker (3; 60) which is locked to the connector body so as to assume a preliminary holding position and released from a locked state at the preliminary holding position thereby to be movable to a detection position when the pipe is inserted into the insertion hole thereby to assume a normal position, wherein the checker (3; 60) is provided with a cover (34; 64) configured to cover the release operation portion (28; 54) of the retainer (2; 50) when the checker (3; 60) assumes the detection position, characterized in that the checker (3; 60) is formed with a pressing piece which is located rearward in the insertion direction of the pipe relative to the locking legs (26; 51) when the checker (3; 60) assumes the detection position, thereby preventing the locking legs (26; 51) from being flexed rearward.