There is provided a projection system including: a projector configured to project an image on a projection surface; and a computer configured to communicate with the projector and instruct the projector to project the image in accordance with an operation by a user. The projector includes a first processor that sends information on an operation state of the projector to the computer while communicating with the computer. The computer includes a display and/or a speaker and a second processor that makes a notification based on the information from the projector by causing the display to display a notification and/or by causing the speaker to output a voice.