Wireless transmitting device and wireless transmitting system

A wireless transmitting device using electric power supplied from a power generating element which can generate the electric power by utilizing mechanical energy externally applied, the wireless transmitting device comprising:

• an electric storage element for storing the electric power generated by the power generating element;
• and
• a wireless transmitting unit for performing a wireless transmitting operation with using the electric power supplied from the electric storage element, the wireless transmitting unit being capable of setting a power consumption amount consumed at one time of the wireless transmitting operation,
• wherein the wireless transmitting device is configured to set a timing when the wireless transmitting unit consumes the electric power and the power consumption amount of the wireless transmitting unit according to electromotive force of the power generating element, and
• wherein when the electromotive force of the power generating element is defined as “E0”, a voltage of the electric storage element at the timing when the wireless transmitting unit consumes the electric power is defined as “E1” and a voltage of the electric storage element after the wireless transmitting unit consumes the electric power is defined as “E2”, the wireless transmitting device sets the timing and the power consumption amount so that a condition of “0.3E0≤(E1+E2)/2≤0.7E0” is satisfied.