Hello and welcome to Bleepingcomputer.
First your English is fine and I understood everything you explained in your post clearly.
Below is a link to the Toshiba web site, it is linked to the support pages of your computer.
Here is the main link. http://www.csd.toshiba.com/cgi-bin/tais/su...mily=1073768663
This link is to a pdf format owners manual. http://www.csd.toshiba.com/cgi-bin/tais/su...mily=1073768663
Your problem is usually related to dust build up inside the laptop or the heat sink on the processor or video card is loose, or needs to be removed and new thermal grease applied.
First thing you want to try is purchasing a can of compressed air designed for blowing out electronic enclosures.
Blow the air through any air vents that you find on the unit.
It may come down to disassembling the laptop to gain access to the fan and heat sink to successfully remove embedded dust from the cooling fins.
Removing the processor's heat sink and applying thermal grease to the processor's head and re-installing the heat sink will help transfer heat away from the processor more efficiently.
Check the video card for dust, there may be a cooling fan tunnel that allows air flow to reach the heat sink, make sure this tunnel is clear of any dust as well and that any heat sink on the video card is clear of dust in its fins.
Please post back the results after you have tried what I suggested.
Good luck and kind regards.