Does the concept of evil spirits occur in Buddhism? Some of the western religions have evil spirits like devils and demons.  Does the concept or belief in evil spirits occur in Buddhism?
It's not always as clear as 'good' or 'evil'. Angry, vengeful spirits also exist in forms of Buddhism. Sometimes also seen as protectors, they can be a source of controversy.

More common is one's own belief in (or, more practically, fear of) something that is indefinitely, and irreparably, sinister or evil. We subscribe to all sorts of interesting notions as children, some things tend to persist. Ultimately, it's what your mind manages to trick you into into feeling; there are plenty of Christians that don't believe that demons exist so it really does depend on the individual.

So, yes to the concept (with emphasis on what neubau mentions about indigenous spirits), but belief is a little more complicated; belief coupled with a healthy dose of ambivalence can be quite common.

For children, I think the boogeyman is rather universal :)