Yes, it does.

Yes it can be shut off so it runs all night but I find that after a couple ours the sound effect loops so that every 5 or 8 seconds it makes a slight squeek sound. I got another sound machine and that one also does it. A lot of people like this product but I found some of the sound effects to be a little harsh (for example the ocean wave one is great but the Seagulls don't sound like real seagulls so much as a squeeky door). I'm thinking this product is still worth 3 stars but I'm puzzled over the rave reviews this product has been getting. For a basic sound machine I think this product is better suited to be priced at $15.00 than $20 I recommend buying a higher priced product. Anyway, mine runs fine if only used for the 30 minute limit but after a few hours they make that slight squeek every 5 to 8 seconds. This might not bother you at all even though it might bother others. It's a cheapo machine at a good price so if you're looking to save money this might be a good device.