Abstract: A weak acid bar soap including a body of a weak acid bar soap 1 having N-long-chain acyl acidic amino-acid salt, water, and a transparentizing agent (at least one of multiple alcohol, hydrocarbon, thiourea, and urea) as a component and having a shape which has at least base 2 and side 4; a waterproof protective film 11 attached to lower side surface of said weak acid bar soap 1. The waterproof protective film 11 is a little bigger than said base 2 of said weak acid bar soap 1 and covers all of said base 2, extending to a lower part of said side 4 continuously from said base 2, attached to said lower side surface of said weak acid bar soap 1 to cover at least said lower part of said side 4, leading edge of said waterproof protective film 11? and said side 4 of said weak acid bar soap 1 are clung tightly to nor make a gap, such that said base 2 and said lower part of said side 4 of said weak acid bar soap 11 are not dissolved by moisture.