1. A wet nonwoven fabric comprising a meta-aramid fiber and a polyphenylene sulfide short fiber, wherein a proportion of the polyphenylene sulfide short fiber at least partially fused in the wet nonwoven fabric is 40% or less, and the wet nonwoven fabric has a dielectric breakdown strength of 17 kV/mm or more.
2. The wet nonwoven fabric according to claim 1, wherein a proportion of the meta-aramid fiber in the wet nonwoven fabric is 15% or more.
3. The wet nonwoven fabric according to claim 1 or 2, wherein a proportion of a meta-aramid fiber fibrillated in the wet nonwoven fabric is 15% or more.
4.- A method for producing the wet nonwoven fabric according to any one of claims 1 to 3, the method comprising subjecting a dry web obtained by fabricating a wet nonwoven fabric containing a meta-aramid fiber and a polyphenylene sulfide short fiber and then by removing moisture to a heating and pressurization treatment at a temperature equal to or higher than a glass transition point of the polyphenylene sulfide short fiber and equal to

or lower than a melting point of the meta-aramid fiber.
5. A laminated sheet comprising the wet nonwoven fabric according to any one of claims 1 to 3 laminated on at least one surface of a thermoplastic resin sheet.
6. The laminated sheet according to claim 5, wherein a thermoplastic resin constituting the thermoplastic resin sheet is selected from polyethylene terephthalate, polyethylene naphthalate, and polyphenylene sulfide.
7- An electrical insulating paper comprising the wet nonwoven fabric according to any one of claims 1 to 3.
8. An electrical insulating sheet comprising the laminated sheet according to claim 5 or 6.