I agree, JW, get an electrician if you are unfamiliar with an electric box.
However, before condeming the breaker, make sure the dryer itself is not drawing too much amperage. This could occur from a variety of reasons - Motor overheating, grounded heating element , drum binding, etc. If you don't have an ampmeter, you might be smart to call a professional as an electrician charges alot of $$$$$$$ and then that might not solve your problem. If you know how to use an ampmeter, check one of the hot lines (usually a black or red wire ) on the incoming voltage. You clamp meter around the wire. If amperage is close to 30 (28 or 29), then the breaker is probably not the problem although it could be both. If its in low 20's , (22 - 24) amperage wise, the problem is probably the breaker is weak.