A screen printing machine configured to move a squeegee by a squeegee moving device along a mask to print solder on a substrate through a through hole of the mask is improved in size and usability. A squeegee-device main body is fixed to a mask frame receiver for holding a mask frame, and a squeegee slide, a squeegee head, and a squeegee-slide driving device are provided on the main body. A position adjusting device including two front/rear-direction adjusting units, one right/left-direction adjusting unit, and one floating support unit is provided between a main body frame of the screen printing machine, and the mask frame receiver and the squeegee-device main body to adjust relative positions of the mask and the substrate by moving the mask frame receiver and the squeegee-device main body together with each other.