Sewing machine

A sewing machine comprising:

• a presser foot attached to a lower end of a presser bar supported by a sewing machine frame so as to be movable up and down, the presser foot depressing a cloth to be sewn;
• a lever linking to the presser foot moves up and down relative to the cloth;
• an actuator moving down the lever at a predefined amount to depress the cloth with the presser foot;
• an elastic body present between the actuator and the presser foot, the elastic body being compressed by the move-down operation of the lever at the predefined amount, and applying, to the presser foot, pushing force that cancels repulsive force from the depressed cloth;
• an encoder detecting an amount the presser foot moves down;
• and
• a calculator setting two timings by monitoring the number of slits per a unit time counted by the encoder, the calculator calculating a thickness of the cloth when no load is applied based on the amount the presser foot moves down detected by the encoder at the two timings during a time period at which the presser foot depresses the cloth and attempts to further move down, wherein the two timings are a first timing set after the number of slits per a unit time changes and a second timing set before the number of slits per a unit time becomes zero.