To provide an oral cavity cleaning device and a nozzle thereof which contribute to enhancing the cleaning effect in an oral cavity.SOLUTION: The oral cavity cleaning apparatus is provided with a nozzle 40 including an inlet through which a cleaning liquid is supplied and a flow path forming portion 50 provided with a flow path FP including an outlet 41A for injecting a cleaning liquid, . The flow path configuring section 50 includes a first constituent part 51 including a first flow path FP 1 constituting the flow path FP and a second constituent part 51 provided on the downstream side of the first constituent part 51 and having a second flow narrower than the first flow path FP 1 A second constituent part 52 including a path FP 2, a third constituent part 53 provided on the downstream side of the second constituent part 52 and including a third channel FP 3 wider than the second channel FP 2, a third constituent part 53 , A reduction portion 55 which is provided on the downstream side of the flow path FP and narrows the flow path FP, and a reduction portion 55 which is provided on the downstream side of the reduction portion 55 and which is wider as it goes from the reduction portion 55 side to the outflow port 41 A side so that cavitation occurs in the cleaning liquid And a fourth constituent part 54 including four flow paths FP 4.(FIG.【課題】口腔内の洗浄効果を高めることに寄与する口腔洗浄装置およびそのノズルを提供する。【解決手段】口腔洗浄装置は、洗浄液が供給される流入口、および、洗浄液を噴射する流出口41Aを含む流路FPが設けられた流路構成部50を含むノズル40と、洗浄液を流入口に供給するポンプとを備える。流路構成部50は、流路FPを構成する第1流路FP1を含む第1構成部51と、第1構成部51の下流側に設けられ、第1流路FP1よりも狭い第2流路FP2を含む第2構成部52と、第2構成部52の下流側に設けられ、第2流路FP2よりも広い第3流路FP3を含む第3構成部53と、第3構成部53の下流側に設けられ、流路FPを狭める縮小部55と、縮小部55の下流側に設けられ、洗浄液にキャビテーションが発生するように縮小部55側から流出口41A側に向かうにつれて広くなる第4流路FP4を含む第4構成部54とを含む。【選択図】図3
