PROBLEM TO BE SOLVED: To provide a filter for a water supply device for pets which can obtain sufficient filtering performance.SOLUTION: A filter 5 for a water supply device for pets which is detachably provided between a water accumulation tank and a water drinking part and is configured that water returning from the water drinking part to the water accumulation tank passes from an upper surface side to a lower surface side in a water supply device for pets in which the water drinking part is provided above the water accumulation tank, and the water supplied from the water accumulation tank to the water drinking part returns to the water accumulation tank is provided. The filter for a water supply device for pets includes: a filter tray 6 in which an outer peripheral wall 62 is provided in a manner to rise on an outer peripheral edge part of a bottom wall 61 where a water passing hole 64 is formed an inner part filter material 71 housed in the filter tray 6 and an upper surface covering filter material 72 which is attached to cover an upper end opening part of the filter tray 6. The filter tray 6 is formed in a manner that a lower side of the outer peripheral wall 62 is positioned inside with respect to an upper side of the outer peripheral wall.SELECTED DRAWING: Figure 6COPYRIGHT: (C)2018,JPO&INPIT【課題】十分な濾過性能が得られるペット用給水器のフィルターを提供する。【解決手段】貯水タンクの上方に水飲み部が設けられ、かつ貯水タンクから水飲み部に供給された水が貯水タンクに戻るようにしたペット用給水器における貯水タンクおよび水飲み部間に着脱自在に設けられ、かつ水飲み部から貯水タンクに戻る水を上面側から下面側に通過させるようにしたペット用給水器のフィルター5を対象とする。通水孔64が形成された底壁61の外周縁部に立ち上がり状に外周壁62が設けられたフィルタートレイ6と、フィルタートレイ6内に収容された内部濾材71と、フィルタートレイ6の上端開口部を被覆するように取り付けられた上面被覆濾材72とを備える。フィルタートレイ6の外周壁62がその下側が上側よりも内側に位置するように形成されている。【選択図】図6