Provided is a hydroponic culture tool with which it is possible to suppress an increase in the internal pressure of a container and to enable the smooth downflow of water when supplying water in a state in which the hydroponic culture tool is mounted on the opening of the container. A hydroponic culture tool (1) with which a water-retaining bed (2) can be mounted on the opening (4) of a container (3), wherein the hydroponic culture tool (1) is configured by being provided with: a bed-holding part (11) that opens upward and has a hollow part (16) in which the bed (2) is disposed, the bed-holding part (11) being inserted into the opening (4) of the container (3) an expanded-diameter section (12) that extends outward from a top-end opening (11a) of the bed-holding part (11) a water passage hole (13) that passes through a bottom surface part (11c) of the bed-holding part (11) and a ventilation passage (14) formed in the outer surface of a peripheral surface part (11b) of the bed-holding part (11), at least a portion of the air passage (14) being constituted by a recessed section (17) for ventilation extending in the extension direction of the bed-holding part (11), the ventilation passage (14) allowing communication between the internal space of the container (3) and the outside air.Linvention concerne un outil de culture hydroponique, avec lequel il est possible de supprimer une augmentation de la pression interne dun contenant et de permettre lécoulement descendant régulier de leau lors de lalimentation en eau dans un état dans lequel loutil de culture hydroponique est monté sur louverture du contenant. Linvention concerne un outil de culture hydroponique (1) avec lequel un lit de rétention deau (2) peut être monté sur louverture (4) dun contenant (3), loutil de culture hydroponique (1) étant configuré en ayant : une partie de maintien de lit (11) qui souvre vers le haut et a une partie creuse (16) dans laquelle le lit (2) est disposé, la partie de maintien de lit (11
