There is a lizard entering in my room & it become pain for me how can I stop entering of lizards in my room

What area of the world are you in?
Which are you in?: House or apartment building?
Are you sure it's a lizard? If so, can you show us what it looks like? Here are some pictures (http://www.google.com/images?hl=en&source=imghp&biw=1142&bih=636&q=lizard&gbv=2&aq=f&aqi=g10&aql=&oq=&gs_rfai=).

In short, a "pesticide" is probably not what you need. Depending on where you are will be the key point in determining what it is and how to stop it from coming into your home.

Give us more info and we can probably help you.

Most reptiles are odor sensitive. If it's just your room you're concerned with you might try sprinkling some paprika around the entrances it uses. Napthalene is a better repellant but it repels most humans as well.