An oil seal comprising: a first seal member which is installed to an inner periphery of a shaft hole in a housing inserting a shaft thereto, wherein said first seal member integrally has an affixation section which is fitted to an inner peripheral surface of the shaft hole in said housing, a main lip which slidably comes into close contact with a peripheral surface of said shaft so as to seal a sealed fluid in an inner side of the machine, and a first dust lip which slidably comes into close contact with the peripheral surface of said shaft so as to seal a foreign material such as a muddy water in the outer side of the machine, characterized in that said oil seal further comprises a second seal member which is installed to an end surface section of said housing in an opening peripheral edge section of said shaft hole, wherein said second seal member integrally has an end surface covering section which covers the end surface section of said housing, an outer peripheral insertion section which is inserted from one side in an axial direction to an outer peripheral surface of said housing and is engaged with a stepped engagement section provided in the outer peripheral surface of said housing so as to prevent said second seal member from coming off from said housing, an inner peripheral insertion section which is inserted to the inner peripheral surface of the shaft hole in said housing from one side in the axial direction, and a second dust lip which slidably comes into close contact with a peripheral surface of said shaft in the outer side of the machine in said first dust lip so as to seal the foreign material such as the muddy water in the outer side of the machine. a first seal member which is installed to an inner periphery of a shaft hole in a housing inserting a shaft thereto, wherein said first seal member integrally has an affixation section which is fitted to an inner peripheral surface of the shaft hole in said housing, a main lip which slidably comes into close contact with a peripheral surface of said shaft so as to seal a sealed fluid in an inner side of the machine, and a first dust lip which slidably comes into close contact with the peripheral surface of said shaft so as to seal a foreign material such as a muddy water in the outer side of the machine, characterized in that said oil seal further comprises a second seal member which is installed to an end surface section of said housing in an opening peripheral edge section of said shaft hole, wherein said second seal member integrally has an end surface covering section which covers the end surface section of said housing, an outer peripheral insertion section which is inserted from one side in an axial direction to an outer peripheral surface of said housing and is engaged with a stepped engagement section provided in the outer peripheral surface of said housing so as to prevent said second seal member from coming off from said housing, an inner peripheral insertion section which is inserted to the inner peripheral surface of the shaft hole in said housing from one side in the axial direction, and a second dust lip which slidably comes into close contact with a peripheral surface of said shaft in the outer side of the machine in said first dust lip so as to seal the foreign material such as the muddy water in the outer side of the machine.