To provide a stain preventing cover for a Western style toilet, which is readily mounted on a toilet bowl and further has a high stain preventing effect.

The stain preventing cover 1 is mounted on the upper surface 3 of the Western style toilet bowl 2, and disposed between the toilet bowl 2 and a toilet seat. The stain preventing cover 1 has an upper surface cover portion 11 including a slant portion 14 and having a substantially U shape, a side cover portion 12 integrally formed with the upper surface cover portion 11 and extending downward along the internal peripheral surface 4 of the toilet bowl, and a rear cover portion 13 attached to both end portions 22a and 22b of the upper surface cover portion 11 and set at the back side of the toilet bowl 2. The slant portion 14 is provided with supporting legs 16 for supporting the upper surface cover portion 11, and a connected portion between the upper surface cover portion 11 and the side cover portion 12 is provided with protruding portions 19 abutting on the toilet bowl 2. Recess portions 21 are formed between the protruding portions 19. The rear cover portion 13 is provided with changeable attaching portions 26 allowing the change in connecting position of the upper surface cover portion 11.