A medical liquid administration device comprising: a flowing portion (113, 114, 142) including a flow path through which a medical liquid is to flow; a medical liquid storage communicating with the flowing portion (113, 114, 142), the medical liquid storage storing the medical liquid that is to be fed to the flowing portion (113, 114, 142); a drive mechanism including a motor configured to generate a driving force for feeding the medical liquid stored in the medical liquid storage to the flow path; a detection unit configured to detect an operating state of the drive mechanism in a detection region that is preset; and a controller (20, 134, 203) configured to control the drive mechanism, the controller (20, 134, 203) being configured to perform determination based on an output from the detection unit, characterized in that the controller (20, 134, 203) stops liquid feeding from the flowing portion (113, 114, 142) in a case where the output from the detection unit is not included in the detection region, then determines occurrence of blockage in the flowing portion (113, 114, 142) when the output of the detection unit is included in the detection region if the motor rotates in a reverse rotation direction to that rotation direction of the motor during the liquid feeding, and determines occurrence of failure in the drive mechanism when the output is not included in the detection region, wherein the flowing portion (113, 114, 142) includes: a first flowing portion (113, 114) including a cannula to be punctured into a living body, the cannula being provided with the flow path through which the medical liquid is to be fed to the living body; and a second flowing portion separably connected to the first flowing portion (113, 114), the second flowing portion forming the flow path from the medical liquid storage to the first flowing portion (113, 114), the controller (20, 134, 203) causes the motor to rotate in a rotation direction identical to the rotation direction of the motor during the liquid feeding, when the controller (20, 134, 203) determines separation of the second flowing portion from the first flowing portion (113, 114) and occurrence of blockage in the flowing portion (113, 114, 142), determines occurrence of blockage in the first flowing portion (113, 114), when the output from the detection unit in the separation of the second flowing portion from the first flowing portion (113, 114) is included in the detection region, and determines occurrence of blockage in the second flowing portion, when the output of the detection unit is not included in the detection region. a flowing portion (113, 114, 142) including a flow path through which a medical liquid is to flow; a medical liquid storage communicating with the flowing portion (113, 114, 142), the medical liquid storage storing the medical liquid that is to be fed to the flowing portion (113, 114, 142); a drive mechanism including a motor configured to generate a driving force for feeding the medical liquid stored in the medical liquid storage to the flow path; a detection unit configured to detect an operating state of the drive mechanism in a detection region that is preset; and a controller (20, 134, 203) configured to control the drive mechanism, the controller (20, 134, 203) being configured to perform determination based on an output from the detection unit, characterized in that the controller (20, 134, 203) stops liquid feeding from the flowing portion (113, 114, 142) in a case where the output from the detection unit is not included in the detection region, then determines occurrence of blockage in the flowing portion (113, 114, 142) when the output of the detection unit is included in the detection region if the motor rotates in a reverse rotation direction to that rotation direction of the motor during the liquid feeding, and determines occurrence of failure in the drive mechanism when the output is not included in the detection region, wherein the flowing portion (113, 114, 142) includes: a first flowing portion (113, 114) including a cannula to be punctured into a living body, the cannula being provided with the flow path through which the medical liquid is to be fed to the living body; and a second flowing portion separably connected to the first flowing portion (113, 114), the second flowing portion forming the flow path from the medical liquid storage to the first flowing portion (113, 114), the controller (20, 134, 203) causes the motor to rotate in a rotation direction identical to the rotation direction of the motor during the liquid feeding, when the controller (20, 134, 203) determines separation of the second flowing portion from the first flowing portion (113, 114) and occurrence of blockage in the flowing portion (113, 114, 142), determines occurrence of blockage in the first flowing portion (113, 114), when the output from the detection unit in the separation of the second flowing portion from the first flowing portion (113, 114) is included in the detection region, and determines occurrence of blockage in the second flowing portion, when the output of the detection unit is not included in the detection region.